Messages in this thread | | | Subject | Re: AMD graphics performance regression in 4.15 and later | From | Christian König <> | Date | Fri, 6 Apr 2018 10:10:53 +0200 |
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Hi Jean,
found the bug reports.
Here is the original bug report from the kernel: https://bugzilla.kernel.org/show_bug.cgi?id=198511
And here is an fdo bug report where we tried to investigate the root cause, but didn't had time for that yet: https://bugs.freedesktop.org/show_bug.cgi?id=105038
Regards, Christian.
Am 06.04.2018 um 10:03 schrieb Christian König: > Hi Jean, > > yeah, that is a known problem. Using huge pages improves the > performance because of better TLB usage, but for the cost of higher > allocation overhead. > > What we found is that firefox is doing something rather strange by > allocating large textures and then just trowing them away again > immediately. > > We mitigated the problem by avoiding the slow coherent DMA code path > on almost all platforms on newer kernels, but essentially somebody > needs to figure out why firefox and/or the user space stack is doing > this constant allocation/freeing of memory. > > There is also a bug tracker on bugs.kernel.org about this, but I can't > find it any more of hand. > > Regards, > Christian. > > Am 06.04.2018 um 02:30 schrieb Jean-Marc Valin: >> Hi, >> >> I noticed a serious graphics performance regression between 4.14 and >> 4.15. It is most noticeable with Firefox (tried FF57 through FF60) and >> causes scrolling to be really choppy/sluggish. I've confirmed that the >> problem is also there on 4.16, while 4.13 works fine. >> >> After a bisection, I've narrowed the regression down to this commit: >> >> commit 648bc3574716400acc06f99915815f80d9563783 >> Author: Christian König <christian.koenig@amd.com> >> Date: Thu Jul 6 09:59:43 2017 +0200 >> >> drm/ttm: add transparent huge page support for DMA allocations v2 >> >> >> Some details about my system: >> Distro: Fedora 27 (up-to-date) >> Video: MSI Radeon RX 560 AERO >> CPU: Dual-socket Xeon E5-2640 v4 (20 cores total) >> RAM: 128 GB ECC >> >> >> As a comparison, when running Firefox with 4.15 on a Lenovo W540 laptop >> (with Intel graphics only) the responsiveness is much better then what >> I'm getting on the Xeon machine above with the Radeon card, so this >> really seems to be an AMD-only issue. >> >> Any way to fix the issue? >> >> Thanks, >> >> Jean-Marc >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel >
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