Hi Am 05.08.19 um 09:28 schrieb Rong Chen: > Hi, > > On 8/5/19 3:02 PM, Feng Tang wrote: >> Hi Thomas, >> >> On Sun, Aug 04, 2019 at 08:39:19PM +0200, Thomas Zimmermann wrote: >>> Hi >>> >>> I did some further analysis on this problem and found that the blinking >>> cursor affects performance of the vm-scalability test case. >>> >>> I only have a 4-core machine, so scalability is not really testable. Yet >>> I see the effects of running vm-scalibility against drm-tip, a revert of >>> the mgag200 patch and the vmap fixes that I posted a few days ago. >>> >>> After reverting the mgag200 patch, running the test as described in the >>> report >>> >>> bin/lkp run job.yaml >>> >>> gives results like >>> >>> 2019-08-02 19:34:37 ./case-anon-cow-seq-hugetlb >>> 2019-08-02 19:34:37 ./usemem --runtime 300 -n 4 --prealloc >>> --prefault >>> -O -U 815395225 >>> 917319627 bytes / 756534 usecs = 1184110 KB/s >>> 917319627 bytes / 764675 usecs = 1171504 KB/s >>> 917319627 bytes / 766414 usecs = 1168846 KB/s >>> 917319627 bytes / 777990 usecs = 1151454 KB/s >>> >>> Running the test against current drm-tip gives slightly worse results, >>> such as. >>> >>> 2019-08-03 19:17:06 ./case-anon-cow-seq-hugetlb >>> 2019-08-03 19:17:06 ./usemem --runtime 300 -n 4 --prealloc >>> --prefault >>> -O -U 815394406 >>> 917318700 bytes / 871607 usecs = 1027778 KB/s >>> 917318700 bytes / 894173 usecs = 1001840 KB/s >>> 917318700 bytes / 919694 usecs = 974040 KB/s >>> 917318700 bytes / 923341 usecs = 970193 KB/s >>> >>> The test puts out roughly one result per second. Strangely sending the >>> output to /dev/null can make results significantly worse. >>> >>> bin/lkp run job.yaml > /dev/null >>> >>> 2019-08-03 19:23:04 ./case-anon-cow-seq-hugetlb >>> 2019-08-03 19:23:04 ./usemem --runtime 300 -n 4 --prealloc >>> --prefault >>> -O -U 815394406 >>> 917318700 bytes / 1207358 usecs = 741966 KB/s >>> 917318700 bytes / 1210456 usecs = 740067 KB/s >>> 917318700 bytes / 1216572 usecs = 736346 KB/s >>> 917318700 bytes / 1239152 usecs = 722929 KB/s >>> >>> I realized that there's still a blinking cursor on the screen, which I >>> disabled with >>> >>> tput civis >>> >>> or alternatively >>> >>> echo 0 > /sys/devices/virtual/graphics/fbcon/cursor_blink >>> >>> Running the the test now gives the original or even better results, >>> such as >>> >>> bin/lkp run job.yaml > /dev/null >>> >>> 2019-08-03 19:29:17 ./case-anon-cow-seq-hugetlb >>> 2019-08-03 19:29:17 ./usemem --runtime 300 -n 4 --prealloc >>> --prefault >>> -O -U 815394406 >>> 917318700 bytes / 659419 usecs = 1358497 KB/s >>> 917318700 bytes / 659658 usecs = 1358005 KB/s >>> 917318700 bytes / 659916 usecs = 1357474 KB/s >>> 917318700 bytes / 660168 usecs = 1356956 KB/s >>> >>> Rong, Feng, could you confirm this by disabling the cursor or blinking? >> Glad to know this method restored the drop. Rong is running the case. > > I set "echo 0 > /sys/devices/virtual/graphics/fbcon/cursor_blink" for > both commits, > and the regression has no obvious change. Ah, I see. Thank you for testing. There are two questions that come to my mind: did you send the regular output to /dev/null? And what happens if you disable the cursor with 'tput civis'? If there is absolutely nothing changing on the screen, I don't see how the regression could persist. Best regards Thomas > commit: > f1f8555dfb9 drm/bochs: Use shadow buffer for bochs framebuffer console > 90f479ae51a drm/mgag200: Replace struct mga_fbdev with generic > framebuffer emulation > > f1f8555dfb9a70a2 90f479ae51afa45efab97afdde testcase/testparams/testbox > ---------------- -------------------------- --------------------------- > %stddev change %stddev > \ | \ > 43394 -20% 34575 ± 3% > vm-scalability/performance-300s-8T-anon-cow-seq-hugetlb/lkp-knm01 > 43393 -20% 34575 GEO-MEAN > vm-scalability.median > > Best Regards, > Rong Chen > >> >> While I have another finds, as I noticed your patch changed the bpp from >> 24 to 32, I had a patch to change it back to 24, and run the case in >> the weekend, the -18% regrssion was reduced to about -5%. Could this >> be related? >> >> commit: >> f1f8555dfb9 drm/bochs: Use shadow buffer for bochs framebuffer console >> 90f479ae51a drm/mgag200: Replace struct mga_fbdev with generic >> framebuffer emulation >> 01e75fea0d5 mgag200: restore the depth back to 24 >> >> f1f8555dfb9a70a2 90f479ae51afa45efab97afdde9 01e75fea0d5ff39d3e588c20ec5 >> ---------------- --------------------------- --------------------------- >> 43921 ± 2% -18.3% 35884 -4.8% >> 41826 vm-scalability.median >> 14889337 -17.5% 12291029 -4.1% >> 14278574 vm-scalability.throughput >> commit 01e75fea0d5ff39d3e588c20ec52e7a4e6588a74 >> Author: Feng Tang <feng.tang@xxxxxxxxx> >> Date: Fri Aug 2 15:09:19 2019 +0800 >> >> mgag200: restore the depth back to 24 >> Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx> >> >> diff --git a/drivers/gpu/drm/mgag200/mgag200_main.c >> b/drivers/gpu/drm/mgag200/mgag200_main.c >> index a977333..ac8f6c9 100644 >> --- a/drivers/gpu/drm/mgag200/mgag200_main.c >> +++ b/drivers/gpu/drm/mgag200/mgag200_main.c >> @@ -162,7 +162,7 @@ int mgag200_driver_load(struct drm_device *dev, >> unsigned long flags) >> if (IS_G200_SE(mdev) && mdev->mc.vram_size < (2048*1024)) >> dev->mode_config.preferred_depth = 16; >> else >> - dev->mode_config.preferred_depth = 32; >> + dev->mode_config.preferred_depth = 24; >> dev->mode_config.prefer_shadow = 1; >> r = mgag200_modeset_init(mdev); >> >> Thanks, >> Feng >> >>> >>> The difference between mgag200's original fbdev support and generic >>> fbdev emulation is generic fbdev's worker task that updates the VRAM >>> buffer from the shadow buffer. mgag200 does this immediately, but relies >>> on drm_can_sleep(), which is deprecated. >>> >>> I think that the worker task interferes with the test case, as the >>> worker has been in fbdev emulation since forever and no performance >>> regressions have been reported so far. >>> >>> >>> So unless there's a report where this problem happens in a real-world >>> use case, I'd like to keep code as it is. And apparently there's always >>> the workaround of disabling the cursor blinking. >>> >>> Best regards >>> Thomas >>> > -- Thomas Zimmermann Graphics Driver Developer SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg)
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