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Message-ID: <fa10b293-9c7f-4904-88bf-4ec6528bd0ef@linaro.org>
Date:   Sun, 3 Dec 2023 02:08:26 +0200
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Subject: Re: [RFC] drm/msm/rd: Check PT_PTRACED for cmdstream dumping
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To:     Rob Clark <robdclark@gmail.com>, dri-devel@lists.freedesktop.org
Cc:     freedreno@lists.freedesktop.org,
        Rob Clark <robdclark@chromium.org>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Sean Paul <sean@poorly.run>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20230914172453.9707-1-robdclark@gmail.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <20230914172453.9707-1-robdclark@gmail.com>
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On 14/09/2023 20:24, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> So, when you want to get a cmdstream trace of some deqp or piglit test,
> but you happen to be running it on the same laptop with full desktop
> env, the current dump-everything firehose of `cat $debugfs/dri/n/rd` is
> quite a bit too much.  Ptrace seemed kind of a natural way to control
> it, ie. either run what you want to trace under gdb or hack in a
> ptrace(PTRACE_TRACEME) call.
> 
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>   drivers/gpu/drm/msm/msm_gem_submit.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

I think this is a good idea, to be able to separate process being 
debugged and all other tasks.

> 
> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
> index a908373cf34b..a105ca1f2102 100644
> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> @@ -979,7 +979,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
>   	/* The scheduler owns a ref now: */
>   	msm_gem_submit_get(submit);
>   
> -	msm_rd_dump_submit(priv->rd, submit, NULL);
> +	if (current->ptrace & PT_PTRACED)
> +		msm_rd_dump_submit(priv->rd, submit, NULL);
>   
>   	pm_runtime_get_sync(&gpu->pdev->dev);
>   

-- 
With best wishes
Dmitry