linux-kernel - Re: [v8,09/12] drm/msm/a6xx: Add traces for preemption

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Message-ID: <281503da-6ac3-496f-8051-d4e03979c1ef@gmail.com>
Date: Wed, 16 Oct 2024 23:28:14 +0200
From: Antonino Maniscalco <antomani103@...il.com>
To: Rob Clark <robdclark@...il.com>
Cc: Kees Bakker <kees@...erbout.nl>, Sean Paul <sean@...rly.run>,
 Konrad Dybcio <konrad.dybcio@...aro.org>,
 Abhinav Kumar <quic_abhinavk@...cinc.com>,
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Marijn Suijten <marijn.suijten@...ainline.org>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Jonathan Corbet <corbet@....net>, linux-arm-msm@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
 Akhil P Oommen <quic_akhilpo@...cinc.com>,
 Neil Armstrong <neil.armstrong@...aro.org>
Subject: Re: [v8,09/12] drm/msm/a6xx: Add traces for preemption

On 10/16/24 10:33 PM, Rob Clark wrote:
> On Wed, Oct 16, 2024 at 5:13 AM Antonino Maniscalco
> <antomani103@...il.com> wrote:
>>
>> On 10/8/24 11:10 PM, Kees Bakker wrote:
>>> Op 03-10-2024 om 18:12 schreef Antonino Maniscalco:
>>>> Add trace points corresponding to preemption being triggered and being
>>>> completed for latency measurement purposes.
>>>>
>>>> Reviewed-by: Akhil P Oommen <quic_akhilpo@...cinc.com>
>>>> Tested-by: Rob Clark <robdclark@...il.com>
>>>> Tested-by: Neil Armstrong <neil.armstrong@...aro.org> # on SM8650-QRD
>>>> Tested-by: Neil Armstrong <neil.armstrong@...aro.org> # on SM8550-QRD
>>>> Tested-by: Neil Armstrong <neil.armstrong@...aro.org> # on SM8450-HDK
>>>> Signed-off-by: Antonino Maniscalco <antomani103@...il.com>
>>>> ---
>>>>    drivers/gpu/drm/msm/adreno/a6xx_preempt.c |  6 ++++++
>>>>    drivers/gpu/drm/msm/msm_gpu_trace.h       | 28 +++++++++++++++++++++
>>>> +++++++
>>>>    2 files changed, 34 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/
>>>> drm/msm/adreno/a6xx_preempt.c
>>>> index
>>>> 21e333cb6342d33425eb96f97bcc853e9b041b36..6803d5af60cc8fb0f2a52ee160ffdbf0e8ef0209 100644
>>>> --- a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
>>>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
>>>> @@ -7,6 +7,7 @@
>>>>    #include "a6xx_gpu.h"
>>>>    #include "a6xx_gmu.xml.h"
>>>>    #include "msm_mmu.h"
>>>> +#include "msm_gpu_trace.h"
>>>>    /*
>>>>     * Try to transition the preemption state from old to new. Return
>>>> @@ -174,6 +175,8 @@ void a6xx_preempt_irq(struct msm_gpu *gpu)
>>>>        set_preempt_state(a6xx_gpu, PREEMPT_NONE);
>>>> +    trace_msm_gpu_preemption_irq(a6xx_gpu->cur_ring->id);
>>>> +
>>>>        /*
>>>>         * Retrigger preemption to avoid a deadlock that might occur
>>>> when preemption
>>>>         * is skipped due to it being already in flight when requested.
>>>> @@ -294,6 +297,9 @@ void a6xx_preempt_trigger(struct msm_gpu *gpu)
>>>>         */
>>>>        ring->restore_wptr = false;
>>>> +    trace_msm_gpu_preemption_trigger(a6xx_gpu->cur_ring->id,
>>>> +        ring ? ring->id : -1);
>>>> +
>>> There is no need for the ternary operator. "ring" should be non-NULL,
>>> otherwise the code would have already crashed.
>>> So the change can just be
>>>       trace_msm_gpu_preemption_trigger(a6xx_gpu->cur_ring->id, ring->id);
>>
>> You are right, we had a similar cleanup but I missed this particular
>> one, thanks for pointing me at it! I apologize for the late response but
>> I've been at XDC and therefore unable to look at my email. I will point
>> this out to Rob since this series is in msm-next to see if I need to
>> send a separate patch to clean this.
> 
> Yes, please send a new commit, I don't want to re-write history on msm-next

Makes sense.
I noticed somebody else has already sent the patch for it 
https://lore.kernel.org/linux-arm-msm/20241011052315.4713-1-everestkc@everestkc.com.np/

> 
> BR,
> -R
> 
>> Best regards,
>> --
>> Antonino Maniscalco <antomani103@...il.com>


Best regards,
-- 
Antonino Maniscalco <antomani103@...il.com>