Like I wrote before, we at Collabora have been working on improving WebKitGTK+ performance for customer projects, such as Apertis. We took the opportunity brought by recent improvements to WebKitGTK+ and GTK+ itself to make the final leg of drawing contents to screen as efficient as possible. And then we went on investigating why so much CPU was still being used in some of our test cases.
The first weird thing we noticed is performance was actually degraded on Wayland compared to running under X11. After some investigation we found a lot of time was being spent inside GTK+, painting the window’s background.
Here’s the thing: the problem only showed under Wayland because in that case GTK+ is responsible for painting the window decorations, whereas in the X11 case the window manager does it. That means all of that expensive blurring and rendering of shadows fell on GTK+’s lap.
You might also be wondering why would painting of window decorations be such a problem, anyway? They should only be repainted when a window changes size or state anyway, which should be pretty rare, right? Right, that is one of the reasons why we had to make it fast, though: the resizing experience was pretty terrible. But we’ll get back to that later.
So I dug into that, made a few tries at understanding the issue and came up with a patch showing how applying the blur was being way too expensive. After a bit of discussion with our own Pekka Paalanen and Benjamin Otte we found the root cause: a fast path was not being hit by pixman due to the difference in scale factors on the shadow mask and the target surface. We made the shadow mask scale the same as the surface’s and voilà, sane performance.
I keep talking about this being a performance problem, but how bad was it? In the following video you can see how huge the impact in performance of this problem was on my very recent laptop with a HiDPI display. The video starts with an Epiphany window running with a patched GTK+ showing a nice demo the WebKit folks cooked for CSS animations and 3D transforms.
After a few seconds I quickly alt-tab to the version running with unpatched GTK+ – I made the window the exact size and position of the other one, so that it is under the same conditions and the difference can be seen more easily. It is massive.
Yes, all of that slow down was caused by repainting window shadows! OK, so that solved the problem for HiDPI displays, made resizing saner, great! But why is GTK+ repainting the window even if only the contents are changing, anyway? Well, that turned out to be an off-by-one bug in the code that checks whether the invalidated area includes part of the window decorations.
If the area being changed spanned the whole window width, say, it would always cause the shadows to be repainted. By fixing that, we now avoid all of the shadow drawing code when we are running full-window animations such as the CSS poster circle or gtk3-demo’s pixbufs demo.
As you can see in the video below, the gtk3-demo running with the patched GTK+ (the one on the right) is using a lot less CPU and has smoother animation than the one running with the unpatched GTK+ (left).
Pretty much all of the overhead caused by window decorations is gone in the patched version. It is still using quite a bit of CPU to animate those pixbufs, though, so some work still remains. Also, the overhead added to integrate cairo and GL rendering in GTK+ is pretty significant in the WebKitGTK+ CSS animation case. Hopefully that’ll get much better from GTK+ 4 onwards.
I had a great time last week and the web engines hackfest! It was the 7th web hackfest hosted by Igalia and the 7th hackfest I attended. I’m almost a local Galician already. Brazilian Portuguese being so close to Galician certainly helps! Collabora co-sponsored the event and it was great that two colleagues of mine managed to join me in attendance.
It had great talks that will eventually end up in videos uploaded to the web site. We were amazed at the progress being made to Servo, including some performance results that blew our minds. We also discussed the next steps for WebKitGTK+, WebKit for Wayland (or WPE), our own Clutter wrapper to WebKitGTK+ which is used for the Apertis project, and much more.
One thing that drew my attention was how many Dell laptops there were. Many collaborans (myself included) and igalians are now using Dells, it seems. Sure, there were thinkpads and macbooks, but there was plenty of inspirons and xpses as well. It’s interesting how the brand make up shifted over the years since 2009, when the hackfest could easily be mistaken with a thinkpad shop.
Back to the actual hackfest: with the recent release of Gnome 3.22 (and Fedora 25 nearing release), my main focus was on dealing with some regressions suffered by users experienced after a change that made putting the final rendering composited by the nested Wayland compositor we have inside WebKitGTK+ to the GTK+ widget so it is shown on the screen.
One of the main problems people reported was applications that use WebKitGTK+ not showing anything where the content was supposed to appear. It turns out the problem was caused by GTK+ not being able to create a GL context. If the system was simply not able to use GL there would be no problem: WebKit would then just disable accelerated compositing and things would work, albeit slower.
The problem was WebKit being able to use an older GL version than the minimum required by GTK+. We fixed it by testing that GTK+ is able to create GL contexts before using the fast path, falling back to the slow glReadPixels codepath if not. This way we keep accelerated compositing working inside WebKit, which gives us nice 3D transforms and less repainting, but take the performance hit in the final “blit”.
The other patch was cooked by Philip Withnall and helped us deal with some performance bottlenecks we were hitting. It improves the performance of painting scroll bars. WebKitGTK+ does its own painting of scrollbars (we do not use the GTK+ widgets for various reasons). It turns out painting scrollbars can be quite a hit when the page is being scrolled fast, if not done efficiently.
Emanuele Aina had a great time learning more about meson to figure out a build issue we had when a more recent GStreamer was added to our jhbuild environment. He came out of the experience rather sane, which makes me think meson might indeed be much better than autotools.
It was a great hackfest, great seeing everyone face to face. We were happy to celebrate Igalia’s 15 years with them. Hope to see everyone again next year =)
Next week our friends at Igalia will be hosting this year’s Web Engines Hackfest. Collabora will be there! We are gold sponsors, and have three developers attending. It will also be an opportunity to celebrate Igalia’s 15th birthday \o/. Looking forward to meet you there! =)
Carlos Garcia has recently released WebKitGTK+ 2.14, the latest stable release. This is a great release that brings a lot of improvements and works much better on Wayland, which is becoming mature enough to be used by default. In particular, it fixes the clipboard, which was one of the main missing features, thanks to Carlos Garnacho! We have also been able to contribute a bit to this release =)
One of the biggest changes this cycle is the threaded compositor, which was implemented by Igalia’s Gwang Yoon Hwang. This work improves performance by not stalling other web engine features while compositing. Earlier this year we contributed fixes to make the threaded compositor work with the web inspector and fixed elements, helping with the goal of enabling it by default for this release.
Wayland was also lacking an accelerated compositing implementation. There was a patch to add a nested Wayland compositor to the UIProcess, with the WebProcesses connecting to it as Wayland clients to share the final rendering so that it can be shown to screen. It was not ready though and there were questions as to whether that was the way to go and alternative proposals were floating around on how to best implement it.
At last year’s hackfest we had discussions about what the best path for that would be where collaborans Emanuele Aina and Daniel Stone (proxied by Emanuele) contributed quite a bit on figuring out how to implement it in a way that was both efficient and platform agnostic.
We later picked up the old patchset, rebased on the then-current master and made it run efficiently as proof of concept for the Apertis project on an i.MX6 board. This was done using the fancy GL support that landed in GTK+ in the meantime, with some API additions and shortcuts to sidestep performance issues. The work was sponsored by Robert Bosch Car Multimedia.
Igalia managed to improve and land a very well designed patch that implements the nested compositor, though it was still not as efficient as it could be, as it was using glReadPixels to get the final rendering of the page to the GTK+ widget through cairo. I have improved that code by ensuring we do not waste memory when using HiDPI.
As part of our proof of concept investigation, we got this WebGL car visualizer running quite well on our sabrelite imx6 boards. Some of it went into the upstream patches or proposals mentioned below, but we have a bunch of potential improvements still in store that we hope to turn into upstreamable patches and advance during next week’s hackfest.
One of the improvements that already landed was an alternate code path that leverages GTK+’s recent GL super powers to render using gdk_cairo_draw_from_gl(), avoiding the expensive copying of pixels from the GPU to the CPU and making it go faster. That improvement exposed a weird bug in GTK+ that causes a black patch to appear when shrinking the window, which I have a tentative fix for.
We originally proposed to add a new gdk_cairo_draw_from_egl() to use an EGLImage instead of a GL texture or renderbuffer. On our proof of concept we noticed it is even more efficient than the texturing currently used by GTK+, and could give us even better performance for WebKitGTK+. Emanuele Bassi thinks it might be better to add EGLImage as another code branch inside from_gl() though, so we will look into that.
Another very interesting igalian addition to this release is support for the MemoryPressureHandler even on systems with no cgroups set up. The memory pressure handler is a WebKit feature which flushes caches and frees resources that are not being used when the operating system notifies it memory is scarce.
We worked with the Raspberry Pi Foundation to add support for that feature to the Raspberry Pi browser and contributed it upstream back in 2014, when Collabora was trying to squeeze as much as possible from the hardware. We had to add a cgroups setup to wrap Epiphany in, back then, so that it would actually benefit from the feature.
With this improvement, it will benefit even without the custom cgroups setups as well, by having the UIProcess monitor memory usage and notify each WebProcess when memory is tight.
Some of these improvements were achieved by developers getting together at the Web Engines Hackfest last year and laying out the ground work or ideas that ended up in the code base. I look forward to another great few days of hackfest next week! See you there o/
For the 6th year in a row, Igalia has organized a hackfest focused on web engines. The 5 years before this one were actually focused on the GTK+ port of WebKit, but the number of web engines that matter to us as Free Software developers and consultancies has grown, and so has the scope of the hackfest.
It was a very productive and exciting event. It has already been covered by Manuel Rego, Philippe Normand, Sebastian Dröge and Andy Wingo! I am sure more blog posts will pop up. We had Martin Robinson telling us about the new Servo engine that Mozilla has been developing as a proof of concept for both Rust as a language for building big, complex products and for doing layout in parallel. Andy gave us a very good summary of where JS engines are in terms of performance and features. We had talks about CSS grid layouts, TyGL – a GL-powered implementation of the 2D painting backend in WebKit, the new Wayland port, announced by Zan Dobersek, and a lot more.
With help from my colleague ChangSeok OH, I presented a description of how a team at Collabora led by Marco Barisione made the combination of WebKitGTK+ and GNOME’s web browser a pretty good experience for the Raspberry Pi. It took a not so small amount of both pragmatic limitations and hacks to get to a multi-tab browser that can play youtube videos and be quite responsive, but we were very happy with how well WebKitGTK+ worked as a base for that.
One of my main goals for the hackfest was to help drive features that were lingering in the bug tracker for WebKitGTK+. I picked up a patch that had gone through a number of iterations and rewrites: the HTML5 notifications support, and with help from Carlos Garcia, managed to finish it and land it at the last day of the hackfest! It provides new signals that can be used to authorize notifications, show and close them.
To make notifications work in the best case scenario, the only thing that the API user needs to do is handle the permission request, since we provide a default implementation for the show and close signals that uses libnotify if it is available when building WebKitGTK+. Originally our intention was to use GNotification for the default implementation of those signals in WebKitGTK+, but it turned out to be a pain to use for our purposes.
GNotification is tied to GApplication. This allows for some interesting features, like notifications being persistent and able to reactivate the application, but those make no sense in our current use case, although that may change once service workers become a thing. It can also be a bit problematic given we are a library and thus have no GApplication of our own. That was easily overcome by using the default GApplication of the process for notifications, though.
The show stopper for us using GNotification was the way GNOME Shell currently deals with notifications sent using this mechanism. It will look for a .desktop file named after the application ID used to initialize the GApplication instance and reject the notification if it cannot find that. Besides making this a pain to test – our test browser would need a .desktop file to be installed, that would not work for our main API user! The application ID used for all Web instances is org.gnome.Epiphany at the moment, and that is not the same as any of the desktop files used either by the main browser or by the web apps created with it.
For the future we will probably move Epiphany towards this new era, and all users of the WebKitGTK+ API as well, but the strictness of GNOME Shell would hurt the usefulness of our default implementation right now, so we decided to stick to libnotify for the time being.
Other than that, I managed to review a bunch of patches during the hackfest, and took part in many interesting discussions regarding the next steps for GNOME Web and the GTK+ and Wayland ports of WebKit, such as the potential introduction of a threaded compositor, which is pretty exciting. We also tried to have Bastien Nocera as a guest participant for one of our sessions, but it turns out that requires more than a notebook on top of a bench hooked up to a TV to work well. We could think of something next time ;D.
I’d like to thank Igalia for organizing and sponsoring the event, Collabora for sponsoring and sending ChangSeok and myself over to Spain from far away Brazil and South Korea, and Adobe for also sponsoring the event! Hope to see you all next year!
Web Engines Hackfest 2014 sponsors: Adobe, Collabora and Igalia
I have been asked by a bunch of friends from outside of Brazil for my opinion regarding the recent elections we had in Brazil, and it is a bit complicated to explain it without some background, so I decided to write this piece providing a bit of history so that people can understand my opinion.
The elections this year were a rematch of our traditional polarization between the workers party (PT) and the social democracy party (PSDB), which has been going on since 1994. PT and PSDB used to be allies. In the 80s, when the dictatorship dropped the law that forbade more than 2 parties, the opposition party, MDB, began breaking up in several smaller ones.
PSDB was founded by politicians and intelectuals who were inspired by Europe’s social democracy and political systems. Parliamentarism, for instance, is one of the historical causes of the party. The workers party had a more grassroots origin, with union leaders, marxist intelectuals and marxist-inspired catholic priests being the main founders. They drew their inspiration from the USSR and Cuba, and were very close to social movements.
Some people have celebrated the reelection of Dilma Roussef as a victory of the left against the right. In my opinion that view is wrong for several reasons. First, because I disagree that PSDB and Aécio Neves in particular are right-wing, both in terms of economics and social/moral issues. Second, because I believe Dilma’s first government has taken a quite severe turn to the right in several topics that matter a lot to me. Since comparisons with PSDB’s government during the 90s has been one of the main strategies of the campaign this year, I’ll argue why I think it was actually a pretty good government with a lot of left in it.
Unlike what happens in most other places, Brazil does not really have an actual right-wing party, economics-wise. Although we might see the birth of a couple in the near future, no current party is really against public health, education and social security being provided by the state as rights, or wants to decrease state size and lower taxes significantly. It should come as no surprise that even though it has undergone a lot of liberal reforms over the last 20 years, Brazil is still a very closed country, with very high import tariffs and a huge presence of the state in the economy. There is a certain consensus about all of that, with disagreements being essentially on implementation details, not goals.
On the other hand, and contrary to popular belief, when it comes to social and moral issues we are a very conservative people. Ironically, the two parties which have been in power over the last 20 years are quite progressive, being historically proponents of diversity, minorities rights, reproductive rights. They have had to compromise on those causes to become viable alternatives, given the conservative nature of the majority of the voters.
Despite their different origins and beliefs, both parties share socialist inclinations and were allies from the onset. That changed in 1992, when president Collor, who had been elected on a runoff against Lula (who PSDB supported), was impeached by Congress for corruption. With no formal political support and a chaotic situation in his hands, Itamar Franco, the vice president, called for a “national union” government to go through the last two years of his term. PSDB answered the call, but the workers party decided against being part of the government.
Fernando Henrique Cardoso, a sociologist who was one of the leaders of PSDB was chosen to lead the Foreign Relations Ministry, but a few months later got nominated to the Economy. At the time, Brazil lived under hyperinflation of close to 1000% a year, and several stabilization plans had been attempted. Economy Ministers did not last very much in office at the time. FHC gathered a team of economists and sponsored their stabilization plan, which turned out to be highly successful: the Plano Real (“Real Plan”). In addition to introducing a new currency, something that was becoming pretty common to Brazilians by then, it also attacked the structural causes of inflation.
Lula was counting on the failure of the Plano Real when he ran against FHC in 1994, but the plan succeeded, giving FHC two terms as president. During those two terms, FHC introduced several institutional changes that made Brazil a saner country. In addition to the hyperinflation, Brazil had lived a debt crises for decades and was still in default. FHC’s team renegotiated the debts, reopened lines of credit, but most importantly, introduced reforms that made the Brazilian finances and financial system credible.
The problem was not even that Brazil had a fiscal déficit, it just did not have any control whatsoever of money supply and budget. Banks, regardless of whether they were private or public, had very little regulation and took advantage of the hyperinflation to hide monstrous holes in their balances. When inflation was gone and regulation became more strict, those became apparent, and it was pretty clear that the system would collapse if nothing was done.
Some people like to say that FHC was a president who ruled for the rich and didn’t care about the poor. I think the way the potential collapse of the banking system was handled is a great counter-example of that. The government passed laws that made the owners of the banks responsible for the financial problems, regardless of whether caused by mismanagement or fraud. If a bank went under, the central bank intervened and added enough money to protect the deposits, but that money was a loan that had to be repaid by the owners of the bank, and the owners’ properties were added as collateral to the loan. As a brazilian journalist once said, the people did not risk losing their deposits, the bankers did risk losing the banks, though. Today, we have a separate fund, filled with money from the banks, that does what the central bank did back then when required.
Compare that to countries where the banking system was saved with tax payer money and executives kept getting huge bonuses regardless, while owners kept their profits. It is hard to find an initiative that is more focused on the public interest against the interest of the rich people who caused the problem. This legislation, called PROER, is still in place today, and it came along with solid regulation of the banking system. It should come as no surprise that Brazil went through the financial crisis of 2008 with not a single hiccup of the banking system and no fear of bank runs. Despite having been against PROER back in the day, Lula celebrated its existence in 2008, when it was clear it was one of the reasons we would not suffer much. He even advertised it as something that should be adopted by the US and Europe.
It is also pretty common to hear that under FHC social questions were not a priority. I believe it is pretty simple to see that that was not the case both by inspecting the growth of social spending and the improvement of social indicators for the period, such as UN’s human development index. One area in which people are particularly critical of the FHC government is the investment on higher education, and they are actually quite right. Brazil has free Federal universities and those did not get a lot of priority in the 90s. However, I would argue that while it is a matter of priorities, it is not one of education versus something else, but rather of what to invest on inside education. The reality is basic education was the priority.
When FHC came to power, Brazil had a significant number of children who were not going to school at all. The goal was to make access to schools universal for young children, and that goal was reached. Every child has been going to school since the early 2000s, and that is a significant achievement which reaches the poorest. While the federal universities are attended essentially by the Brazilian elite, given the difficulty of passing the exams and the relative lack of quality of free public schools compared to private ones, which is still a reality to this day, investment on getting children to even go to school for the early years has a significant impact on the lives of the poorest.
It is important to remember that getting every child to go to school is also what gave birth to one of the most celebrated programs from the Lula era: Bolsa Família (“Family Allowance”) is a direct money transfer to poor families, particularly those who have children and has been an important contribution to lowering inequality and getting people out of extreme poverty. To get the money, the families need to ensure their children are 1) attending school and 2) getting vaccinated.
That program comes from the FHC government, in which it was created with the name Bolsa Escola (“School Allowance”), in its turn inspired by a program of the same name by governor Cristovam Buarque, from PT. What Lula did, and he deserves a lot of credit for this, was to merge a series of smaller programs with Bolsa Escola, and then expand the program to ensure it got to more and more people. Interestingly, during the announcement of the program he credited the idea of doing that to a state governor from PSDB. You can see why I think these two should be allies again.
When faced with all these arguments, people will eventually say that FHC was bad because he privatized companies and used orthodox economic policies. Well, if that is what it takes, then we’ll have to take Lula down with him, because his first term was essentially a continuation of FHC’s second term: orthodox economic policies to keep inflation down, along with privatization of several state-owned companies and banks. But Lula, whom I voted for and whose government I believe was a good one, is not my subject: Dilma is.
On Lula’s second term, Dilma gained a lot of power when other major leaders of PT went down for corruption. She became second in command and started leading several programs. A big believer in developmentalism, she started pushing for a bigger role of the state in the coordination of the productive sector, with a clear focus on growing the industrial base.
One of the initiatives she sponsored was a sizable increase on the number and size of subsidized loans given out by the national development bank (BNDES). Brazil started an unnofficial “national champions” program, where the government elected a few big companies to get a huge amount of subsidized credit.
The goal was for these selected firms to get big enough to be competitive on the global market. The criteria for the choices is completely opaque, if it even exists, and includes handing out milions in subsidized credit for Eike Batista, who became Brazil’s richest enterpreneur for a while, and lost pretty much everything when it became clear the oil would not be pumping out of his camps after all, sinking with them a huge amount of public funds invested by BNDES.
The way this policy was enacted, it is unclear how much it really costs in terms of public funds: the Brazilian treasury emits debt to capitalize, lends that money to BNDES with higher than market interest, and BNDES then lends it out to the big companies with a lower than market interest rate. Although it is obviously unsustainable, the problem does not yet show in the balance because the grace period for BNDES debt with the treasury is 2040. The fact that this has a cost and, perhaps more importantly, a huge opportunity cost is not clear because it is not part of the government budget. Why are we putting money in this rather than quadrupling Bolsa Família, which studies show generates 1,78 reais in GDP for every 1 real invested? Worse, why are we not even updating Bolsa Família enough to cover inflation?
When Dilma got elected in 2010, the first signs were pretty bad. She was already seen as someone who did not care much for the environment, and on her first month in power she made good on that promise by pushing to get the Belo Monte Dam building started as soon as possible regardless of conditionalities being satisfied. To this day there are several issues with how the building of the dam is going: the handling of the indigenous people and the small city nearby are lacking, conditionalities are not met.
Beyond Belo Monte, indigenous leaders are being assassinated, deforestation in the Amazon forest has increased by 122% in 2014 alone. Dilma’s answer to people who question her on these kinds of issues is essentially: “would you rather not have electric power?”
Her populist authoritarian nature and obsession with industry are also pretty evident when it comes to her policies in the energy area as a whole. She showed up in national tv on the eve of our independence day celebration to announce a reduction in electric tariffs, mainly for industry, but also for homes. Nobody really knew how. The following week she sent a fast-track project to Congress to automatically renew concessions of power grid operators, requiring those who accepted it to lower tariffs, instead of doing an auction, which was already necessary anyway because the concessions were up on 2015. There was no discussion with stakeholders, there was just a populist announcement and a great deal of rhethoric to paint anyone who opposed as being against the people.
And now, everything went into the crapper because that represented a breach of contract that required indemnification, and we had a pretty bad drought that made power more expensive given the need to turn on the thermal generators. Combining the costs of the thermal generation, indemnity, and financial fallout that the grid operators suffered, we are already at 105 billion reais and counting, nobody knows how high the cost will reach. Any reduction in tariffs has long been invalidated. And the fact that industry has lowered production significantly ends up being good news, we would probably be under rationing already if that was not the case.
You would expect someone who fought a dictatorship to be pretty good in terms of human and civil rights. What we see in reality is a lack of respect for those things. During the world cup, Dilma has put the army on the streets and has supported arbitrary behaviour from state polices throughout the country. They jailed a bunch of demonstrators preemptively. No shit. The would be demonstrators were kept in jail throghout the tournament under false accusations. Dilma’s Minister of Justice said several times that the case against them was solid and that the arrests were legal, but it turned out the case simply did not exist. Just this week we had a number of executions orchestrated by policemen in the state of Pará and there is zero reaction from the federal government.
In the oil industry, Dilma has enacted a policy of subsidizing gas prices by using a fixed price that used to be lower than the international prices (it is no longer the case with the fall in international prices). That would not be a problem if Brazil was selfsufficient in oild and gas, which we are not: we had to import a significant amount of both. The implicit subsidy cost Petrobrás a huge amount of cash – the more gas it sold, the bigger the losses. This lead not only to decreasing the company’s market value (it is a state-controlled, but open company), but to reducing its capacity of investment as well.
That is more problematic than it sounds because, with our current concession model, every single oil camp needs to have Petrobrás as a member of the consortium. Limiting the company’s investment capacity limits the rate at which our pre-salt oil camps can be explored and thus the speed at which we can become selfsufficient. Chicken and egg anyone?
To make things worse, Dilma has made policies that lowered taxes on car production, used to foster economic activity during the crisis in 2008-2010, essentially permanent. This lead to a significant increase in traffic and polution on Brazilian cities, while at the same time increasing the pressure on Petrobrás, which had to import more and more gas. Meanwhile, Brazilian cities suffer from a severe lack of mobility infrastructure. A recent study has shown that Brazil has spend almost twice as much subsidized money on pro-car policies than on pro-mass transit projects. Talk about good usage of public funds.
One of the only remaining good news the government was still able to mention was the constant reduction in extreme poverty. Dilma was actually ellected promising to erradicate extreme poverty and changed the government’s slogan to “A rich country is a country with no poverty” (País rico é país sem pobreza). Well, it turns out all of these policies caused inequality and extreme poverty both to stop falling as of 2013. And given the policies were actually deepened in 2014, I believe it is very likely we’ll see an increase in both when we get the data for 2014, next year.
Other than that, her policies ended up being a complete failure. Despite giving tax benefits to several sectors, investment has fallen, growth has fallen and inflation is quite high at 6,6% for the last 12 months. In terms of minorities, her government has been a severe set back, with the government going back on educational material against homophoby saying it would not do “advertisement of sexual choice”, and going back on a decree that allowed the public health system to perform abortions on the cases allowed by the law (essentially if the woman has been raped).
Looking at Dilma’s policies, I really can’t see that much of the left, honestly. So why, you might ask, has this victory been deemed a victory of the left over the right? My explanation is the aura the workers party still manages to keep over itself. There’s a notion that whatever PT does, it will still be more to the left than PSDB, which I think is just crazy.
There is also a fair amount of idealizing Dilma just because she is Lula’s protegé. People will forgive anything, provided it is the workers party doing it. Thankfully, the number of people aligned on the left that supported the candidate from PSDB this election tells me this is changing quite rapidly. Hopefully that leads to PT having to reinvent itself, and get in touch with the left again.
For the fifth year in a row the fearless WebKitGTK+ hackers have gathered in A Coruña to bring GNOME and the web closer. Igalia has organized and hosted it as usual, welcoming a record 30 people to its office. The GNOME foundation has sponsored my trip allowing me to fly the cool 18 seats propeller airplane from Lisbon to A Coruña, which is a nice adventure, and have pulpo a feira for dinner, which I simply love! That in addition to enjoying the company of so many great hackers.
The goals for the hackfest have been ambitious, as usual, but we made good headway on them. Web the browser (AKA Epiphany) has seen a ton of little improvements, with Carlos splitting the shell search provider to a separate binary, which allowed us to remove some hacks from the session management code from the browser. It also makes testing changes to Web more convenient again. Jon McCan has been pounding at Web’s UI making it more sleek, with tabs that expand to make better use of available horizontal space in the tab bar, new dialogs for preferences, cookies and password handling. I have made my tiny contribution by making it not keep tabs that were created just for what turned out to be a download around. For this last day of hackfest I plan to also fix an issue with text encoding detection and help track down a hang that happens upon page load.
Martin Robinson and myself have as usual dived into the more disgusting and wide-reaching maintainership tasks that we have lots of trouble pushing forward on our day-to-day lives. Porting our build system to CMake has been one of these long-term goals, not because we love CMake (we don’t) or because we hate autotools (we do), but because it should make people’s lives easier when adding new files to the build, and should also make our build less hacky and quicker – it is sad to see how slow our build can be when compared to something like Chromium, and we think a big part of the problem lies on how complex and dumb autotools and make can be. We have picked up a few of our old branches, brought them up-to-date and landed, which now lets us build the main WebKit2GTK+ library through cmake in trunk. This is an important first step, but there’s plenty to do.
Under the hood, Dan Winship has been pushing HTTP2 support for libsoup forward, with a dead-tree version of the spec by his side. He is refactoring libsoup internals to accomodate the new code paths. Still on the HTTP front, I have been updating soup’s MIME type sniffing support to match the newest living specification, which includes specification for several new types and a new security feature introduced by Internet Explorer and later adopted by other browsers. The huge task of preparing the ground for a one process per tab (or other kinds of process separation, this will still be topic for discussion for a while) has been pushed forward by several hackers, with Carlos Garcia and Andy Wingo leading the charge.
Other than that I have been putting in some more work on improving the integration of the new Web Inspector with WebKitGTK+. Carlos has reviewed the patch to allow attaching the inspector to the right side of the window, but we have decided to split it in two, one providing the functionality and one the API that will allow browsers to customize how that is done. There’s a lot of work to be done here, I plan to land at least this first patch durign the hackfest. I have also fought one more battle in the never-ending User-Agent sniffing war, in which we cannot win, it looks like.
I am very happy to be here for the fifth year in a row, and I hope we will be meeting here for many more years to come! Thanks a lot to Igalia for sponsoring and hosting the hackfest, and to the GNOME foundation for making it possible for me to attend! See you in 2014!
For a while now the git repository used for packaging WebKitGTK+ has been broken. Broken as in nobody was able to clone it. In addition to that, the packaging workflow had been changing over time, from a track-upstream-git/patches applied one to a import-orig-only/patches-not-applied one.
After spending some more time trying to unbreak the repository for the third time I decided it might be a good time for a clean up. I created a new repository, imported all upstream versions for series 1.2.x (which is in squeeze), 1.6.x (unstable), and 1.7.x (experimental). I also imported packaging-related commis for those versions using git format-patch and black magic.
One of the good things about doing this move, and which should make hacking the WebKitGTK+ debian package more pleasant and accessible can be seen here:
kov@goiaba ~/s/debian-webkit> du -sh webkit/.git webkit.old/.git
If you care about the old repository, it’s on git.debian.org still, named old-webkit.git. Enjoy!
So, I intended to be completely away from my computer during my vacations, but hey. I have been interested in this new extension Apple added to the C language a little while ago which introduces the equivalent of closures to C. Today I spent a few minutes looking into it and writing a few tests with the help of clang.
Here’s something I came up with, to use a block as the callback for a GIO asynchronous call:
One of my side projects for these last months was to enroll on the online Introduction to AI class, with Peter Norvig and Sebastian Thrun, professors at Stanford. Through it I also learned about the Kahn Academy. I must say that getting to know these efforts made me feel similar to when I found Free Software: it’s hard to believe that such great things exist!
I learned some really cool stuff, and was also introduced to the amazing work of Sebastian Thrun with self-driving cars, it was an awesome experience! Last weekend I took the final exam, and today I got the certificate of accomplishment. It was delivered as a signed PDF which can be checked with a certificate they provided, pretty neat. I’m very happy, and motivated to enroll on more such courses in the future =). Now it’s time to cool down, though. My vacations start today, and on the weekend I’ll travel to the sunny Fortaleza, in northeastern Brazil, to enjoy some nice beaches and get some tan. See you next year!
It’s been a couple days since I returned from this year’s WebKitGTK+ hackfest in A Coruña, Spain. The weather was very nice, not too cold and not too rainy, we had great food, great drinks and I got to meet new people, and hang out with old friends, which is always great!
I think this was a very productive hackfest, and as usual a very well organized one! Thanks to the GNOME Foundation for the travel sponsorship, to our friends at Igalia for doing an awesome job at making it happen, and to Collabora for sponsoring it and granting me the time to go there! We got a lot done, and although, as usual, our goals list had many items not crossed, we did cross a few very important ones. I took part in discussions about the new WebKit2 APIs, got to know the new design for GNOME’s Web application, which looks great, discussed about Accelerated Compositing along with Joone, Alex, Nayan and Martin Robinson, hacked libsoup a bit to port the multipart/x-mixed-replace patch I wrote to the awesome gio-based infrastructure Dan Winship is building, and some random misc.
The biggest chunk of time, though, ended up being devoted to a very uninteresting (to outsiders, at least), but very important task: making it possible to more easily reproduce our test results. TL;DR? We made our bots’ and development builds use jhbuild to automatically install dependencies; if you’re using tarballs, don’t worry, your usual autogen/configure/make/make install have not been touched. Now to the more verbose version!
For a couple years now we have supported an increasingly complex and very demanding automated testing infrastructure. We have three buildbot slaves, one provided by Collabora (which I maintain), and two provided by Igalia (maintained by their WebKitGTK+ folks). Those bots build as many check ins as possible with 3 different configurations: 32 bits release, 64 bits release, and 64 bits debug.
In addition to those, we have another bot called the EWS, or Early Warning System. There are two of those at this moment: one VM provided by Collabora and my desktop, provided by myself. These bots build every patch uploaded to the bugzilla, and report build failures or passes (you can see the green bubbles). They are very important to our development process because if the patch causes a build failure for our port people can often know that before landing, and try fixes by uploading them to bugzilla instead of doing additional commits. And people are usually very receptive to waiting for EWS output and acting on it, except when they take way too long. You can have an idea of what the life of an EWS bot looks like by looking at the recent status for the WebKitGTK+ bots.
Maintaining all of those bots is at times a rather daunting task. The tests require a very specific set of packages, fonts, themes and icons to always report the same size for objects in a render. Upgrades, for instance, had to be synchronized, and usually involve generating new baselines for a large number of tests. You can see in these instructions, for instance, how strict the environment requirements are – yes, we need specific versions of fonts, because they often cause layouts to change in size! At one point we had tests fail after a compiler upgrade, which made rounding act a bit different!
So stability was a very important aspect of maintaining these bots. All of them have the same version of Debian, and most of the packages are pinned to the same version. On the other hand, and in direct contradition to the stability requirement, we often require bleeding edge versions of some libraries we rely on, such as libsoup. Since we started pushing WebKitGTK+ to be libsoup-only, its own progress has been pretty much driven by WebKitGTK+’s requirements, and Dan Winship has made it possible to make our soup backend much, much simpler and way more featureful. That meant, though, requiring very recent versions of soup.
To top it off, for anyone not running Debian testing and tracking the exact same versions of packages as the bots it was virtually impossible to get the tests to pass, which made it very difficult for even ourselves to make sure all patches were still passing before committing something. Wow, what a mess.
So a few weeks back Martin Robinson came up with a proposed solution, which, as he says, is the “nuclear bomb” solution. We would have a jhbuild environment which would build and install all of the dependencies necessary for reproducing the test expectations the bots have. So over the first three days of the hackfest Martin and myself hacked away in building scripts, buildmaster integration, a jhbuild configuration, a jhbuild modules file, setting up tarballs, and wiring it all in a way that makes it convenient for the contributors to get along with. You’ll notice that our buildslaves now have a step just before compiling called “updated gtk dependencies” (gtk is the name we use for our port in the context of WebKit), which runs jhbuild to install any new dependencies or version bumps we added. You can also see that those instructions I mentioned above became a tad simpler.
It took us way more time than we thought for the dust to settle, but it eventually began to. The great thing of doing it during the hackfest was that we could find and fix issues with weird configurations on the spot! Oh, you build with AR_FLAGS=cruT and something doesn’t like it? OK, we fix it so that the jhbuild modules are not affected by that variable. Oh, turns out we missed a dependency, no problem, we add it to the modules file or install them on the bots, and then document the dependency. I set up a very clean chroot which we could use for trying out changes so as to not disrupt the tree too much for the other hackfest participants, and I think overall we did good.
By the time we were done our colleagues who ran other distributions such as Fedora were already being able to get a substantial improvements to the number of tests passing, and so did we! Also, the ability to seamlessly upgrade all the bots with a simple commit made it possible for us to very easily land a change that required a very recent (as in unreleased) version of soup which made our networking backend way simpler. All that red looks great, doesn’t it? And we aren’t done yet, we’ll certainly be making more tweaks to this infrastructure to make it more transparent and more helpful to the users (contributors and other people interested in running the tests).
If you’ve been hit by the instability we caused, sorry about that, poke mrobinson or myself in the #webkitgtk+ IRC channel on FreeNode, and we’ll help you out or fix any issues. If you haven’t, we hope you enjoy all the goodness that a reproducible testing suite has to offer! That’s it for now, folks, I’ll have more to report on follow-up work started at the hackfest soon enough, hopefully =).