An additional note: Most Windows boxes have an AV installed while most linux boxes don't. Never underestimate the sluggishness of AVs.
M-A On Wed, Oct 28, 2009 at 11:05 AM, Evan Martin <[email protected]> wrote: > > On Tue, Oct 27, 2009 at 9:11 PM, Adam Barth <[email protected]> wrote: >> My three laptops have relatively comparable hardware and run Chrome on >> Windows, Mac, and Linux respectively. The Linux version of Chrome >> feels ridiculously faster than Windows and Mac. Do we understand why >> this is? Can we make Windows and Mac feel that fast too? > > My first instinct is to say because (1) we're awesome and (2) Linux is > awesome, but I'd prefer to have facts back it up. :) > > There's a "perf" link on http://build.chromium.org that has builders > tracking various metrics. If we get perf tests for the behaviors you > care about, we can better compare and improve them. > > On the other hand, I'm not sure if the hardware lines up between > platforms so maybe the comparisons I do below are not valid... > >> General observations: > > General comments: Linux tends to be "lighter" which means it does > better on older hardware, so depending on what sorts of laptops you're > talking about that could be a major factor. Windowses later than 2000 > or so need surprising amounts of hardware to run well. (I don't > mention Mac below because there hasn't been much performance work > there yet.) > >> 1) Scroll performance is extremely good. Even on Gmail, I can only >> get the mouse to lead the scroll bar by a dozen pixels. On Slashdot, >> it doesn't even look like I can do that. > > On "plain" pages (one scrollbar on the right, no Flash) scrolling is > literally shifting the pixels down. On Linux we do this by sending a > command to the X server, which is a single process that even has the > graphics drivers built in so it talks directly to your graphics card > and can in theory do a hardware-accelerated copy. I would expect this > to be pretty fast. > > However, Gmail is a "complicated" page (the main scrollbar is an > iframe) so in that case I guess rendering speed is getting involved. > There I'd expect Windows Chrome to be faster because the compiler is > better and there have been more people looking at performance (I saw > in another thread that tcmalloc, currently only used on Windows, > improved the page cycler by 50%?). > > The page cycler perf graphs are intended to test rendering speed. Do > the numbers match your perception? I can't get the right graphs to > load right now. It looks like spew from NOTIMPLEMENTED()s may be > obscuring the data. > >> 2) Tab creation is very fast. Maybe the zygote is helping here? Can >> we pre-render the NTP on other platforms? > > The zygote is paused right at process start, before we've even started > a renderer. On the other hand Windows process creation is more > expensive. > > There is a "new tab" graph that attempts to measure this. The various > lines on the graph are tracking how quickly we get to each stage in > constructing the page. We hit the first line 20ms faster on Linux > than Windows likely due to the zygote and "slow" Windows process > creation, but process startup seems to be a relatively small part of > the total time. Linux hits other lines later and Linux and Windows > hit the finish line at around the same time. > > In your case, I wonder if you have more history accumulated on your > Windows profile, making the new tab computation more expensive than > the equivalent one on the Linux box. > > I'd expect the faster file system on Linux to eventually be help here. > (My experience with git has been you get an order of magnitude slower > each step from Linux->Mac->Windows, but that could be git or > hardware-specific.) > >> 3) Startup time is faster than calculator. > > I'm not sure if you're kidding. Do you mean Windows calculator? > Maybe there's something wrong with your Windows box -- maybe a virus > scanner or disk indexer or some other crap procmon will show is > continually thrashing your computer. Or maybe you have a spare Chrome > instance on another virtual desktop on your Linux box so clicking the > Chrome button is just telling it to show another window. > > The startup tests are intended to track startup performance, and again > the Windows graphs are much better than the Linux ones. However, the > difference between the two is milliseconds and my experience as a user > is that Chrome rarely starts that fast, so I wonder if these graphs > are really measuring what a user perceives (which frequently involves > disk). > > In the limit, I'd expect us to pay a lot more on Linux due to using > more libraries, GTK initialization, round trips to the X server, etc. > but I don't know much about Windows here. > > > > --~--~---------~--~----~------------~-------~--~----~ Chromium Developers mailing list: [email protected] View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev -~----------~----~----~----~------~----~------~--~---
