[Bug 111305] `ttm_bo_handle_move_mem` sometimes takes more than 50 ms

[Bug 111305] `ttm_bo_handle_move_mem` sometimes takes more than 50 ms

[bugzilla-daemon]

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https://bugs.freedesktop.org/show_bug.cgi?id=111305

            Bug ID: 111305
           Summary: `ttm_bo_handle_move_mem` sometimes takes more than 50
                    ms
           Product: DRI
           Version: XOrg git
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/AMDgpu
          Assignee: dri-devel@lists.freedesktop.org
          Reporter: pmenzel+bugs.freedesktop.org@molgen.mpg.de

Created attachment 144954
  --> https://bugs.freedesktop.org/attachment.cgi?id=144954&action=edit
Screenshot from callgraph excerpt

With Linux 5.3-rc3 and pm-graph’s `sleepgraph.py` [1] measuring suspend times
on the Dell OptiPlex 5040 with an external AMD graphics card, the driver needs
2.1 seconds to suspend the device, which is too long.

    $ lspci -nn -s 01:
    01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc.
[AMD/ATI] Oland XT [Radeon HD 8670 / R7 250/350] [1002:6610] (rev 81)
    01:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Cape
Verde/Pitcairn HDMI Audio [Radeon HD 7700/7800 Series] [1002:aab0]

Here is the time:

    0000:01:00.0 suspend (2170.017 ms @ 5037.143762 to 5039.313779)

Looking into the call graph, 1.4 s are spent in `ttm_bo_evict_mm`.

    ttm_bo_evict_mm [ttm] (1438.050 ms @ 5037.601941)

As you can see in the attached screenshot, there are some
`ttm_bo_handle_move_mem` call which take several milliseconds adding up to the
long time.

    - ttm_mem_evict_first [ttm] (304.860 ms @ 5037.705809)
        _raw_spin_lock
        mutex_trylock (0.000 ms @ 5037.705809)
        + ttm_bo_del_from_lru [ttm]
        - ttm_bo_evict [ttm] (304.857 ms @ 5037.705810)
            amdgpu_evict_flags [amdgpu] (0.000 ms @ 5037.705810)
            ttm_bo_mem_space [ttm] (0.001 ms @ 5037.705811)
            ttm_bo_handle_move_mem [ttm] (304.853 ms @ 5037.705812)

[1]: https://github.com/intel/pm-graph

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[Bug 111305] `ttm_bo_handle_move_mem` sometimes takes more than 50 ms

[bugzilla-daemon]

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https://bugs.freedesktop.org/show_bug.cgi?id=111305

--- Comment #1 from Alex Deucher <alexdeucher@gmail.com> ---
The contents of vram have to be moved to system memory on suspend since vram is
powered off.  Depending on general memory pressure at suspend time it may take
a while to get the contexts of vram into system ram.

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[Bug 111305] `ttm_bo_handle_move_mem` sometimes takes more than 50 ms

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https://bugs.freedesktop.org/show_bug.cgi?id=111305

--- Comment #2 from Paul Menzel <pmenzel+bugs.freedesktop.org@molgen.mpg.de> ---
(In reply to Alex Deucher from comment #1)
> The contents of vram have to be moved to system memory on suspend since vram
> is powered off.  Depending on general memory pressure at suspend time it may
> take a while to get the contexts of vram into system ram.

Just to clarify, the VRAM on the external graphics device is powered off,
correct?

Are there any tools to analyze these delays?

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[Bug 111305] `ttm_bo_handle_move_mem` sometimes takes more than 50 ms

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https://bugs.freedesktop.org/show_bug.cgi?id=111305

--- Comment #3 from Alex Deucher <alexdeucher@gmail.com> ---
(In reply to Paul Menzel from comment #2)
> 
> Just to clarify, the VRAM on the external graphics device is powered off,
> correct?

Correct.

> 
> Are there any tools to analyze these delays?

I guess profiling the relevant functions in ttm.  See if we are waiting on
pages, etc.

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[Bug 111305] `ttm_bo_handle_move_mem` sometimes takes more than 50 ms

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https://bugs.freedesktop.org/show_bug.cgi?id=111305

Martin Peres <martin.peres@free.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |MOVED

--- Comment #4 from Martin Peres <martin.peres@free.fr> ---
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been
closed from further activity.

You can subscribe and participate further through the new bug through this link
to our GitLab instance: https://gitlab.freedesktop.org/drm/amd/issues/886.

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