From: "Christian König" <christian.koenig@amd.com>
To: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Herring <robh@kernel.org>,
Greg KH <gregkh@linuxfoundation.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Anholt, Eric" <eric@anholt.net>,
Pekka Paalanen <ppaalanen@gmail.com>,
amd-gfx list <amd-gfx@lists.freedesktop.org>,
Alex Deucher <Alexander.Deucher@amd.com>,
Lucas Stach <l.stach@pengutronix.de>,
"Wentland, Harry" <Harry.Wentland@amd.com>,
Qiang Yu <yuq825@gmail.com>
Subject: Re: [PATCH v4 11/14] drm/amdgpu: Guard against write accesses after device removal
Date: Fri, 29 Jan 2021 16:16:21 +0100 [thread overview]
Message-ID: <07dceec0-0be9-1531-0357-353f04d1cb2b@amd.com> (raw)
In-Reply-To: <7834dbdf-27ad-f21d-b58b-2772a598ea8a@amd.com>
Am 28.01.21 um 18:23 schrieb Andrey Grodzovsky:
>
> On 1/19/21 1:59 PM, Christian König wrote:
>> Am 19.01.21 um 19:22 schrieb Andrey Grodzovsky:
>>>
>>> On 1/19/21 1:05 PM, Daniel Vetter wrote:
>>>> [SNIP]
>>> So say writing in a loop to some harmless scratch register for many
>>> times both for plugged
>>> and unplugged case and measure total time delta ?
>>
>> I think we should at least measure the following:
>>
>> 1. Writing X times to a scratch reg without your patch.
>> 2. Writing X times to a scratch reg with your patch.
>> 3. Writing X times to a scratch reg with the hardware physically
>> disconnected.
>>
>> I suggest to repeat that once for Polaris (or older) and once for
>> Vega or Navi.
>>
>> The SRBM on Polaris is meant to introduce some delay in each access,
>> so it might react differently then the newer hardware.
>>
>> Christian.
>
>
> See attached results and the testing code. Ran on Polaris (gfx8) and
> Vega10(gfx9)
>
> In summary, over 1 million WWREG32 in loop with and without this patch
> you get around 10ms of accumulated overhead ( so 0.00001 millisecond
> penalty for each WWREG32) for using drm_dev_enter check when writing
> registers.
>
> P.S Bullet 3 I cannot test as I need eGPU and currently I don't have one.
Well if I'm not completely mistaken that are 100ms of accumulated
overhead. So around 100ns per write. And even bigger problem is that
this is a ~67% increase.
I'm not sure how many write we do during normal operation, but that
sounds like a bit much. Ideas?
Christian.
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next prev parent reply other threads:[~2021-01-29 15:16 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 21:01 [PATCH v4 00/14] RFC Support hot device unplug in amdgpu Andrey Grodzovsky
2021-01-18 21:01 ` [PATCH v4 01/14] drm/ttm: Remap all page faults to per process dummy page Andrey Grodzovsky
2021-01-18 21:48 ` Alex Deucher
2021-01-19 8:41 ` Christian König
2021-01-19 13:56 ` Daniel Vetter
2021-01-25 15:28 ` Andrey Grodzovsky
2021-01-27 14:29 ` Andrey Grodzovsky
2021-02-02 14:21 ` Daniel Vetter
2021-01-18 21:01 ` [PATCH v4 02/14] drm: Unamp the entire device address space on device unplug Andrey Grodzovsky
2021-01-18 21:01 ` [PATCH v4 03/14] drm/ttm: Expose ttm_tt_unpopulate for driver use Andrey Grodzovsky
2021-01-18 21:01 ` [PATCH v4 04/14] drm/sched: Cancel and flush all oustatdning jobs before finish Andrey Grodzovsky
2021-01-18 21:49 ` Alex Deucher
2021-01-19 8:42 ` Christian König
2021-01-19 9:50 ` Christian König
2021-01-18 21:01 ` [PATCH v4 05/14] drm/amdgpu: Split amdgpu_device_fini into early and late Andrey Grodzovsky
2021-01-19 8:45 ` Christian König
2021-01-18 21:01 ` [PATCH v4 06/14] drm/amdgpu: Add early fini callback Andrey Grodzovsky
2021-01-18 21:01 ` [PATCH v4 07/14] drm/amdgpu: Register IOMMU topology notifier per device Andrey Grodzovsky
2021-01-18 21:52 ` Alex Deucher
2021-01-19 8:48 ` Christian König
2021-01-19 13:45 ` Daniel Vetter
2021-01-19 21:21 ` Andrey Grodzovsky
2021-01-19 22:01 ` Daniel Vetter
2021-01-20 4:21 ` Andrey Grodzovsky
2021-01-20 8:38 ` Daniel Vetter
[not found] ` <1a5f7ccb-1f91-91be-1cb1-e7cb43ac2c13@amd.com>
2021-01-21 10:48 ` Daniel Vetter
2021-01-20 5:01 ` Andrey Grodzovsky
2021-01-20 19:38 ` Andrey Grodzovsky
2021-01-21 10:42 ` Christian König
2021-01-18 21:01 ` [PATCH v4 08/14] drm/amdgpu: Fix a bunch of sdma code crash post device unplug Andrey Grodzovsky
2021-01-19 8:51 ` Christian König
2021-01-18 21:01 ` [PATCH v4 09/14] drm/amdgpu: Remap all page faults to per process dummy page Andrey Grodzovsky
2021-01-19 8:52 ` Christian König
2021-01-18 21:01 ` [PATCH v4 10/14] dmr/amdgpu: Move some sysfs attrs creation to default_attr Andrey Grodzovsky
2021-01-19 7:34 ` Greg KH
2021-01-19 16:36 ` Andrey Grodzovsky
2021-01-19 17:47 ` Greg KH
2021-01-19 19:04 ` Alex Deucher
2021-01-19 19:16 ` Andrey Grodzovsky
2021-01-19 19:41 ` Greg KH
2021-01-19 8:53 ` Christian König
2021-01-18 21:01 ` [PATCH v4 11/14] drm/amdgpu: Guard against write accesses after device removal Andrey Grodzovsky
2021-01-19 8:55 ` Christian König
2021-01-19 15:35 ` Andrey Grodzovsky
2021-01-19 15:39 ` Christian König
2021-01-19 18:05 ` Daniel Vetter
2021-01-19 18:22 ` Andrey Grodzovsky
2021-01-19 18:59 ` Christian König
2021-01-19 19:16 ` Andrey Grodzovsky
2021-01-20 19:34 ` Andrey Grodzovsky
2021-01-28 17:23 ` Andrey Grodzovsky
2021-01-29 15:16 ` Christian König [this message]
2021-01-29 17:35 ` Andrey Grodzovsky
2021-01-29 19:25 ` Christian König
2021-02-05 16:22 ` Andrey Grodzovsky
2021-02-05 22:10 ` Daniel Vetter
2021-02-05 23:09 ` Andrey Grodzovsky
2021-02-06 14:18 ` Daniel Vetter
2021-02-07 21:28 ` Andrey Grodzovsky
2021-02-07 21:50 ` Daniel Vetter
2021-02-08 9:37 ` Christian König
2021-02-08 9:48 ` Daniel Vetter
2021-02-08 10:03 ` Christian König
2021-02-08 10:11 ` Daniel Vetter
2021-02-08 13:59 ` Christian König
2021-02-08 16:23 ` Daniel Vetter
2021-02-08 22:15 ` Andrey Grodzovsky
2021-02-09 7:58 ` Christian König
2021-02-09 14:30 ` Andrey Grodzovsky
2021-02-09 15:40 ` Christian König
2021-02-10 22:01 ` Andrey Grodzovsky
2021-02-12 15:00 ` Andrey Grodzovsky
2021-02-08 22:09 ` Andrey Grodzovsky
2021-02-09 8:27 ` Christian König
2021-02-09 9:46 ` Daniel Vetter
2021-01-18 21:01 ` [PATCH v4 12/14] drm/scheduler: Job timeout handler returns status Andrey Grodzovsky
2021-01-19 7:53 ` Christian König
2021-01-19 17:47 ` Luben Tuikov
2021-01-19 18:53 ` Christian König
2021-01-18 21:01 ` [PATCH v4 13/14] drm/sched: Make timeout timer rearm conditional Andrey Grodzovsky
2021-01-18 21:01 ` [PATCH v4 14/14] drm/amdgpu: Prevent any job recoveries after device is unplugged Andrey Grodzovsky
2021-01-19 14:16 ` [PATCH v4 00/14] RFC Support hot device unplug in amdgpu Daniel Vetter
2021-01-19 17:31 ` Andrey Grodzovsky
2021-01-19 18:08 ` Daniel Vetter
2021-01-19 18:18 ` Andrey Grodzovsky
2021-01-20 9:05 ` Daniel Vetter
2021-01-20 14:19 ` Andrey Grodzovsky
2021-01-20 15:59 ` Daniel Vetter
2021-02-08 5:59 ` Andrey Grodzovsky
2021-02-08 7:27 ` Daniel Vetter
2021-02-09 4:01 ` Andrey Grodzovsky
2021-02-09 9:50 ` Daniel Vetter
2021-02-09 15:34 ` Andrey Grodzovsky
2021-02-18 20:03 ` Andrey Grodzovsky
2021-02-19 10:24 ` Daniel Vetter
2021-02-24 16:30 ` Andrey Grodzovsky
2021-02-25 10:25 ` Daniel Vetter
2021-02-25 16:12 ` Andrey Grodzovsky
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