[PATCH] drm/amd/powerply: fix power reading on Fiji

[Zhu, Rex]

>> Power value is wrong reported by customer.

Hi Eric,

What is the wrong value customer reported?

In my end, there is no big difference between 20ms and 200ms or 2s. I tested on Fiji/Tonga when gpu idle or running fullscreen glxgears.

why need 50 ms?

How long does the SMU core take to complete one cycle of dpm tasks? I tested, it is less than 1 ms.

So when we delay 20 ms, The output is the average value of more than 20 sampling.

Best Regards
Rex


From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf Of Deucher, Alexander
Sent: Friday, March 30, 2018 4:00 AM
To: Huang, JinHuiEric; amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH] drm/amd/powerply: fix power reading on Fiji


Fiji and tonga I presume.  The current code seems to work fine on tonga at least.



Alex

________________________________
From: Huang, JinHuiEric
Sent: Thursday, March 29, 2018 3:58:42 PM
To: Deucher, Alexander; amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
Subject: Re: [PATCH] drm/amd/powerply: fix power reading on Fiji


Right. This is only for Fiji. We should use PPSMC_MSG_GetCurrPkgPwr on poaris.



Thanks,

Eric

On 2018-03-29 03:54 PM, Deucher, Alexander wrote:

Thanks. Patch is:

Acked-by: Alex Deucher <alexander.deucher at amd.com><mailto:alexander.deucher at amd.com>

Care to make a patch to use PPSMC_MSG_GetCurrPkgPwr on polaris boards so we don't have to worry about the delay on them?



Alex

________________________________
From: Huang, JinHuiEric
Sent: Thursday, March 29, 2018 3:40:22 PM
To: Deucher, Alexander; amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
Subject: Re: [PATCH] drm/amd/powerply: fix power reading on Fiji


This reading method is shared with AGT tool only on Fiji, because SMU FW doesn't support PPSMC_MSG_GetCurrPkgPwr message on Fiji. But since polaris10, PPSMC_MSG_GetCurrPkgPwr has been supported. We also use PPSMC_MSG_GetCurrPkgPwr on vega which SMU FW control sampling period. Driver will not care about it.



Eric

On 2018-03-29 03:31 PM, Deucher, Alexander wrote:

Do you know what the sampling period is on vega?  We should try and be consistent.  How about making this selectable via hwmon:

power[1-*]_average_interval       Power use averaging interval.  A poll

                          notification is sent to this file if the

                          hardware changes the averaging interval.

                          Unit: milliseconds

                          RW



power[1-*]_average_interval_max   Maximum power use averaging interval

                          Unit: milliseconds

                          RO



power[1-*]_average_interval_min   Minimum power use averaging interval

                          Unit: milliseconds

                          RO



Then the user can select the interval they want.



Alex

________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org><mailto:amd-gfx-bounces at lists.freedesktop.org> on behalf of Eric Huang <JinHuiEric.Huang at amd.com><mailto:JinHuiEric.Huang at amd.com>
Sent: Thursday, March 29, 2018 3:21:52 PM
To: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
Cc: Huang, JinHuiEric
Subject: [PATCH] drm/amd/powerply: fix power reading on Fiji

Power value is wrong reported by customer. It is a regression by

commit a7c7bc4c0c47eaac77b8fa92f0672032df7f4254
Author: Rex Zhu <Rex.Zhu at amd.com><mailto:Rex.Zhu at amd.com>
Date:   Mon Mar 27 15:32:59 2017 +0800

    drm/amd/powerplay: reduce sample period time

    for power readings.

    Signed-off-by: Rex Zhu <Rex.Zhu at amd.com><mailto:Rex.Zhu at amd.com>
    Reviewed-by: Alex Deucher <alexander.deucher at amd.com><mailto:alexander.deucher at amd.com>
    Signed-off-by: Alex Deucher <alexander.deucher at amd.com><mailto:alexander.deucher at amd.com>

The theoretical sampling period is from 50ms to 4sec, original 2sec
is long but correct, and 20ms is too short. change it to more
reasonable 200ms.

Signed-off-by: Eric Huang <JinHuiEric.Huang at amd.com><mailto:JinHuiEric.Huang at amd.com>
---
 drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
index a03b7fe..7631d80 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
@@ -3377,7 +3377,8 @@ static int smu7_get_gpu_power(struct pp_hwmgr *hwmgr,
                         "Failed to start pm status log!",
                         return -1);

-       msleep_interruptible(20);
+       /* Sampling period from 50ms to 4sec */
+       msleep_interruptible(200);

         PP_ASSERT_WITH_CODE(!smum_send_msg_to_smc(hwmgr,
                         PPSMC_MSG_PmStatusLogSample),
--
2.7.4

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