On 2018-10-28 11:27 a.m., Gustaw Smolarczyk wrote: > pon., 17 wrz 2018 o 18:24 Michel Dänzer <mic...@daenzer.net> napisał(a): >> >> On 2018-09-15 3:04 a.m., Marek Olšák wrote: >>> On Fri, Sep 14, 2018 at 4:53 AM, Michel Dänzer <mic...@daenzer.net> wrote: >>>> >>>> Last but not least, this doesn't solve the issue of apps such as >>>> blender, which spawn their own worker threads after initializing OpenGL >>>> (possibly not themselves directly, but via the toolkit or another >>>> library; e.g. GTK+4 uses OpenGL by default), inheriting the thread >>>> affinity. >>>> >>>> >>>> Due to these issues, setting the thread affinity needs to be disabled by >>>> default, and only white-listed for applications where it's known safe >>>> and beneficial. This sucks, but I'm afraid that's the reality until >>>> there's better API available which allows solving these issues. >>> >>> We don't have the bandwidth to maintain whitelists. This will either >>> have to be always on or always off. >>> >>> On the positive side, only Ryzens with multiple CCXs get all the >>> benefits and disadvantages. >> >> In other words, only people who spent relatively large amounts of money >> for relatively high-end CPUs will be affected (I'm sure they'll be glad >> to know that "common people" aren't affected. ;). Affected applications >> will see their performance decreased by a factor of 2-8 (the number of >> CCXs in the CPU). >> >> OTOH, only a relatively small number of games will get a significant >> benefit from the thread affinity, and the benefit will be smaller than a >> factor of 2. This cannot justify risking a performance drop of up to a >> factor of 8, no matter how small the risk. >> >> Therefore, the appropriate mechanism is a whitelist. > > Hi, > > What was the conclusion of this discussion? I don't see any > whitelist/blacklist for this feature. > > I have just tested blender and it still renders on only a single CCX > on mesa from git master. Also, there is a bug report that suggests > this regressed performance in at least one game [1].
I hooked up that bug report to the 18.3 blocker bug. > If you think enabling it by default is the way to go, we should also > implement a blacklist so that it can be turned off in such cases. I stand by my opinion that a white-list is appropriate, not a black-list. It's pretty much the same as mesa_glthread. > [1] https://bugs.freedesktop.org/show_bug.cgi?id=108330 -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
