[Mesa-dev] [Bug 87886] constant fps drops with Intel and Radeon on Source games

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=87886

--- Comment #5 from Stéphane Travostino <stephane.travostino at gmail.com> ---
(In reply to Eero Tamminen from comment #1)
> Has your performance regressed?  This fall there have been some compiler
> frontend improvements that allow e.g. more inlining to be done for some
> shaders, and as result compilation can take (in worst case even several
> times) longer than earlier. See bug 86140.

I've always seen lag with the Radeon card, although it seems to be slowly
getting better since my first tests 12 months ago. I don't have numbers to
support that claim though.

> 
> Recompile messages come from the backend which is separate for AMD and
> Intel, i.e. you may need to file separate bugs for each (Intel one would be
> for "Drivers/DRI/i965" component).

I've opened a generic bug report since this affects two different card vendors,
and even if Intel has some specific bugs or performance issues, I suspect the
problem is in the driver-independent code.

> 
> 
> > This happens with Counter Strike: Global Offensive and Left 4 Dead 2 (only games available for testing), also when standing still in an empty black room.
> 
> Please give detailed instructions, how one can reach an "empty black room"
> where Mesa will do constant shader recompiles.  Preferably in single player
> / tutorial level which doesn't require hours of playing.

Left 4 Dead 2 instructions: load a single player game, Dead Center map 1, load
the game: as soon as the game starts (helicopter scene) you get a noticeable
slowdown, probably due to map loading.
>From that point on, every few seconds you should get a noticeable lag every few
seconds. You can get a bigger slowdown when meleeing zombies or the explosion
about 30 seconds into the game.

Note: this affects every map, and is constant in every point of the map. I
written about the empty room just to point out that this happen even when there
is nothing being rendered on the screen (apart from HUD).

> 
> (I haven't seen anything like that on HSW in those games.)
> 
> Alternatively, you could provide Apitrace trace.

Will do.

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