Profiling X, KDE, KWin and friends...

[Ilyes Gouta]

Yesterday, I tried hooking valgrind --trace-children with the startkde
executable but the window manager (kwin) failed to start after waiting for
almost 20min. It was really a slow process.

-Ilyes

On Thu, Apr 16, 2009 at 9:52 AM, Ilyes Gouta <ilyes.gouta at gmail.com> wrote:

>
> Alright, thank you guys for the information. I'm gonna try sysprof out, it
> looks like it's THE tool I'm looking for!
>
> Regards,
> Ilyes Gouta.
>
> 2009/4/15 Adam Jackson <ajax at redhat.com>
>
>> On Wed, 2009-04-15 at 12:12 -0700, Adam Williamson wrote:
>> > On Wed, 2009-04-15 at 12:12 +0100, Ilyes Gouta wrote:
>> > > Hi,
>> > >
>> > > I'm running Fedora 10 on my old Thinkpad R50e, which has a Pentium M
>> > > and an intel 855GM graphics card and I'm not happy with the
>> > > performance of KDE, Kwin, Xserver and al. where sometimes, I can
>> > > clearly see a given window getting its background cleared and its
>> > > content redrawn slowly. I remember I didn't have annoying artifacts
>> > > when I was running Windows, three years ago on the same machine. I
>> > > don't have composition enabled or any fancy thing in my KDE setup. So
>> > > basically, I'm asking if you guys know about any profiling tool that
>> > > would enable me to see where the system is spending its time,
>> > > especially when rendering the desktop.
>> >
>> > I'm fairly sure performance regressions are one of the known issues with
>> > older Intel chips (pre-i915, basically) on the newer versions of the
>> > intel driver, so you may want to check redhat and freedesktop bugzillas
>> > first to see if anyone's reported similar problems.
>>
>> There's at least one known problem with 855 and 865, which is that we
>> don't quite have the cache flushing logic right yet (partly chipset
>> bugs, partly inadequate CPUs on those boards), which means you end up
>> invalidating all write-back mappings on every buffer you ask the GPU to
>> execute (which means cache flush, which means a lot of memory write
>> traffic).  Not the fastest thing ever.
>>
>> If this is what you're hitting, sysprof would show you spending an
>> inordinate amount of time in i915_gem_execbuffer() in the kernel.
>>
>> sysprof is an _awesome_ tool, by the way.
>>
>> - ajax
>>
>> --
>> fedora-devel-list mailing list
>> fedora-devel-list at redhat.com
>> https://www.redhat.com/mailman/listinfo/fedora-devel-list
>>
>
>
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