[Nouveau] qemu -display sdl,gl=on also eats CPU

[Ilia Mirkin]

The DDX eating CPU isn't intrinsically bad. Did you check where perf
says the CPU time is going? Could be doing copies/etc.

On Mon, Aug 17, 2020 at 12:52 AM Andrew Randrianasulu
<randrianasulu at gmail.com> wrote:
>
> I was testing Ilia's patches for ddx, and while they definitely helped for Xorg itself,
> qemu still eats a lot of CPU if launched like this
>
> qemu-system-x86_64 -cdrom ~/Downloads/ISO/slax-English-US-7.0.8-x86_64.iso -m 1G -display sdl,gl=on -enable-kvm
>
> and left for few hours.
>
> top - 07:38:01 up 18:05,  2 users,  load average: 2,00, 1,89, 1,83
> Tasks: 224 total,   3 running, 221 sleeping,   0 stopped,   0 zombie
> %Cpu(s): 40,6 us,  6,1 sy,  0,3 ni, 49,2 id,  0,8 wa,  0,0 hi,  2,9 si,  0,0 st
> MiB Mem :  11875,3 total,   3535,7 free,   3339,3 used,   5000,3 buff/cache
> MiB Swap:   1145,0 total,   1131,2 free,     13,8 used.   4874,7 avail Mem
>
>   PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
>  6215 guest     20   0 1455160 951768  45560 R  99,3   7,8 710:44.44 qemu-system-x86
> 12655 guest     20   0 2459848   1,5g 126708 R  59,1  12,6 217:53.21 seamonkey
>  1991 root      20   0  178112 109500  28840 S  20,9   0,9 187:20.05 Xorg
>  2068 guest     20   0  104932  51660  30764 S   5,6   0,4  54:08.99 ktorrent
>  6031 root      20   0       0      0      0 I   2,0   0,0   0:20.24 kworker/0:3-events
>  3697 guest     20   0  382432  20308  13696 S   1,7   0,2  91:38.13 xmms
>  2064 guest     20   0   55868  37048  23976 S   1,3   0,3   2:38.47 konsole
>  2319 guest     20   0   40160  21248  18548 S   1,3   0,2  12:36.63 gkrellm
>  5853 root      20   0       0      0      0 I   0,7   0,0   0:07.21 kworker/2:2-events
>
> opreport after  operf --pid 6215 said:
>
> opreport
> Using /home/guest/botva/src/xf86-video-nouveau/oprofile_data/samples/ for samples directory.
> CPU: AMD64 family15h, speed 3800 MHz (estimated)
> Counted CPU_CLK_UNHALTED events (CPU Clocks not Halted) with a unit mask of 0x00 (No unit mask) count 100000
> CPU_CLK_UNHALT...|
>   samples|      %|
> ------------------
>    260163 100.000 qemu-system-x86_64
>         CPU_CLK_UNHALT...|
>           samples|      %|
>         ------------------
>            144120 55.3960 nouveau_dri.so
>             87990 33.8211 libdrm_nouveau.so.2.0.0
>             11783  4.5291 libpixman-1.so.0.38.0
>              7884  3.0304 kallsyms
>              5310  2.0410 libc-2.30.so
>               689  0.2648 ld-2.30.so
>               519  0.1995 nouveau
>               501  0.1926 qemu-system-x86_64
>               456  0.1753 ttm
>               239  0.0919 kvm
>               211  0.0811 kvm_amd
>                81  0.0311 libpthread-2.30.so
>                76  0.0292 drm
>                49  0.0188 libSDL2-2.0.so.0.12.0
>                43  0.0165 libxcb.so.1.1.0
>                36  0.0138 libGL.so.1.2.0
>                31  0.0119 libX11.so.6.3.0
>                24  0.0092 snd_pcm
>                23  0.0088 snd_hda_codec
>                20  0.0077 libglib-2.0.so.0.5800.1
>                11  0.0042 snd_timer
>                 9  0.0035 libglapi.so.0.0.0
>                 8  0.0031 libdrm.so.2.4.0
>                 7  0.0027 snd_aloop
>                 7  0.0027 snd_hda_intel
>                 7  0.0027 libxshmfence.so.1.0.0
>                 7  0.0027 libgcc_s.so.1
>                 5  0.0019 [vdso] (tgid:6215 range:0xf7f9f000-0xf7f9ffff)
>                 5  0.0019 snd_hda_core
>                 4  0.0015 r8169
>                 3  0.0012 libahci
>                 2 7.7e-04 ohci_hcd
>                 2 7.7e-04 libxcb-present.so.0.0.0
>                 1 3.8e-04 libatomic.so.1.1.0
>
> so, may be similar fix needed for mesa, too?
>
> ow, I started it in ddx src directory :} need to cleanup there. But at least data is 100
>
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