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. 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 Date: Fri Aug 2 15:09:19 2019 +0800 mgag200: restore the depth back to 24 Signed-off-by: Feng Tang 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 > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel