Re: [chromium-dev] Interesting performance characteristics of http://a.qoid.us/google.html
On Mon, Jan 11, 2010 at 9:04 PM, Chris Evans cev...@chromium.org wrote: Hi, I found this interesting: http://a.qoid.us/google.html Because it's clearly very non-JavaScript focused (just a CSS rotation) and yet the browsers exhibit very different performance characteristics. All on my underpowered Windows laptop, Chrome 3 4: smooth. Very nice anti-aliased accurate rendering. Safari 4: not quite as smooth; less fps but still not bad. Text / lines more jagged and text wobbles during the rotation. The other browsers do not support the CSS used / required for this demo. There was a similar version, but using SVG animation to do something very similar. (It's currently offline). Firefox and Opera were able to attempt the rotation of this one but both performed much worse that Safari and Chrome. Anyone know why Chrome, and to a certain extent Safari, are so much better on this non-JS test? Is the Skia library underpinning Chrome superior? There's also a difference between Chrome Windows and Chrome Linux. Whilst Chrome Linux performs smoothly, the text is clearly jiggling around and even getting more / less bold throughout the rotation cycle. Doesn't do that on Windows. Any ideas? I imagine the problems on Linux are the same as they were on Windows, where the underlying graphics layer wants to place glyphs aligned on pixel boundaries. This gives rounding problems and the letters jump around. I spent several weeks making the rotations and transparency on Windows text and form controls look good. Brett -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev
Re: [chromium-dev] Interesting performance characteristics of http://a.qoid.us/google.html
On Tue, Jan 12, 2010 at 10:17 AM, Brett Wilson bre...@chromium.org wrote: I imagine the problems on Linux are the same as they were on Windows, where the underlying graphics layer wants to place glyphs aligned on pixel boundaries. This gives rounding problems and the letters jump around. I spent several weeks making the rotations and transparency on Windows text and form controls look good. Can you elaborate a bit on what you did? (I write this as maybe the person who will need to fight with this at some point, but practically I wonder if it'll eventually fall on you. :P) -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev
Re: [chromium-dev] Interesting performance characteristics of http://a.qoid.us/google.html
On Tue, Jan 12, 2010 at 11:33 AM, Evan Martin e...@chromium.org wrote: On Tue, Jan 12, 2010 at 10:17 AM, Brett Wilson bre...@chromium.org wrote: I imagine the problems on Linux are the same as they were on Windows, where the underlying graphics layer wants to place glyphs aligned on pixel boundaries. This gives rounding problems and the letters jump around. I spent several weeks making the rotations and transparency on Windows text and form controls look good. Can you elaborate a bit on what you did? (I write this as maybe the person who will need to fight with this at some point, but practically I wonder if it'll eventually fall on you. :P) This is the code in SkiaFontWin.cpp. That's non-ideal, and it would be better to have Skia get the outlines itself and use the Skia path. I don't actually know where the rounding problems occur on Linux. Skia should be fine with it, but its probably in the way it interacts with FreeType (maybe a glyph cache that requires being pixel-aligned?) Brett -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev
Re: [chromium-dev] Interesting performance characteristics of http://a.qoid.us/google.html
Chromium is spending nearly all of its time inside Skia, so it's likely Skia vs CG differences: Welcome to pprof! For help, type 'help'. (pprof) top Total: 1590 samples 592 37.2% 37.2% 592 37.2% SkRegion::Spanerator::Spanerator 89 5.6% 42.8% 89 5.6% sk_memset32_SSE2 87 5.5% 48.3% 135 8.5% TT_RunIns 71 4.5% 52.8% 71 4.5% S32_opaque_D32_filter_DXDY 58 3.6% 56.4% 58 3.6% SkAlphaRuns::Break 52 3.3% 59.7% 996 62.6% walk_edges - James On Tue, Jan 12, 2010 at 1:38 AM, Eric Seidel esei...@chromium.org wrote: I've filed https://bugs.webkit.org/show_bug.cgi?id=33515 On Mon, Jan 11, 2010 at 9:04 PM, Chris Evans cev...@chromium.org wrote: Hi, I found this interesting: http://a.qoid.us/google.html Because it's clearly very non-JavaScript focused (just a CSS rotation) and yet the browsers exhibit very different performance characteristics. All on my underpowered Windows laptop, Chrome 3 4: smooth. Very nice anti-aliased accurate rendering. Safari 4: not quite as smooth; less fps but still not bad. Text / lines more jagged and text wobbles during the rotation. The other browsers do not support the CSS used / required for this demo. There was a similar version, but using SVG animation to do something very similar. (It's currently offline). Firefox and Opera were able to attempt the rotation of this one but both performed much worse that Safari and Chrome. Anyone know why Chrome, and to a certain extent Safari, are so much better on this non-JS test? Is the Skia library underpinning Chrome superior? There's also a difference between Chrome Windows and Chrome Linux. Whilst Chrome Linux performs smoothly, the text is clearly jiggling around and even getting more / less bold throughout the rotation cycle. Doesn't do that on Windows. Any ideas? Cheers Chris -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev
Re: [chromium-dev] Interesting performance characteristics of http://a.qoid.us/google.html
On Mon, Jan 11, 2010 at 11:01 PM, Evan Martin e...@chromium.org wrote: On Mon, Jan 11, 2010 at 9:04 PM, Chris Evans cev...@chromium.org wrote: The other browsers do not support the CSS used / required for this demo. There was a similar version, but using SVG animation to do something very similar. (It's currently offline). Firefox and Opera were able to attempt the rotation of this one but both performed much worse that Safari and Chrome. Anyone know why Chrome, and to a certain extent Safari, are so much better on this non-JS test? Is the Skia library underpinning Chrome superior? I'm not certain, but it sounds like you're comparing CSS rotations in the Chrome/Safari case and SVG rotations in the other, so I'm not sure it's a fair comparison. (Unless you mean to say Chrome/Safari were more performant for the SVG demo as well.) Yes, that's what I meant. The SVG demo was pretty much the same: applying a rotation transform to an iframe of www.google.com. It just happens to be supported on more of the major browsers (everything except IE). Cheers Chris Two anecdotal comments: - In my experience (on Linux) Firefox had really poor SVG performance, and that (for example) canvas performs a lot better. I think none of the engines have done much work on SVG, in part because basically nobody uses it on the web except for demos like this. - Also in my experience Chrome+Skia tends to be faster but sometimes less smooth than Safari's CG. See also all of Dean's Pre3d demos. There's also a difference between Chrome Windows and Chrome Linux. Whilst Chrome Linux performs smoothly, the text is clearly jiggling around and even getting more / less bold throughout the rotation cycle. Doesn't do that on Windows. Any ideas? I don't know much about how this rotation business works, but if I had to guess from looking at it I'd say hinting is getting involved. -- Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev
