[PATCH] drm/amdgpu/mes: fix mes ring buffer overflow

Xiao, Jack Jack.Xiao at amd.com
Mon Jul 22 08:46:48 UTC 2024


[AMD Official Use Only - AMD Internal Distribution Only]

>> Can you try to reduce num_hw_submission for the MES ring?

Smaller num_hw_submission should not help for this issue, for Mes work without drm scheduler like legacy kiq. Smaller num_hw_submission will result in smaller mes ring size and more waiting time.

Regards,
Jack
________________________________
From: Christian König <ckoenig.leichtzumerken at gmail.com>
Sent: Monday, 22 July 2024 16:20
To: Xiao, Jack <Jack.Xiao at amd.com>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; Deucher, Alexander <Alexander.Deucher at amd.com>
Subject: Re: [PATCH] drm/amdgpu/mes: fix mes ring buffer overflow

Thx, but in that case this patch here then won't help either it just mitigates the problem.

Can you try to reduce num_hw_submission for the MES ring?

Thanks,
Christian.

Am 22.07.24 um 05:27 schrieb Xiao, Jack:

[AMD Official Use Only - AMD Internal Distribution Only]

>> I think we rather need to increase the MES ring size instead.

Unfortunately, it doesn't work. I guess mes firmware has limitation.

Regards,
Jack

________________________________
From: Christian König <ckoenig.leichtzumerken at gmail.com><mailto:ckoenig.leichtzumerken at gmail.com>
Sent: Friday, 19 July 2024 23:44
To: Xiao, Jack <Jack.Xiao at amd.com><mailto:Jack.Xiao at amd.com>; amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org> <amd-gfx at lists.freedesktop.org><mailto:amd-gfx at lists.freedesktop.org>; Deucher, Alexander <Alexander.Deucher at amd.com><mailto:Alexander.Deucher at amd.com>
Subject: Re: [PATCH] drm/amdgpu/mes: fix mes ring buffer overflow

Am 19.07.24 um 11:16 schrieb Jack Xiao:
> wait memory room until enough before writing mes packets
> to avoid ring buffer overflow.
>
> Signed-off-by: Jack Xiao <Jack.Xiao at amd.com><mailto:Jack.Xiao at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/mes_v11_0.c | 18 ++++++++++++++----
>   drivers/gpu/drm/amd/amdgpu/mes_v12_0.c | 18 ++++++++++++++----
>   2 files changed, 28 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c b/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
> index 8ce51b9236c1..68c74adf79f1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
> @@ -168,7 +168,7 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        const char *op_str, *misc_op_str;
>        unsigned long flags;
>        u64 status_gpu_addr;
> -     u32 status_offset;
> +     u32 seq, status_offset;
>        u64 *status_ptr;
>        signed long r;
>        int ret;
> @@ -196,6 +196,13 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        if (r)
>                goto error_unlock_free;
>
> +     seq = ++ring->fence_drv.sync_seq;
> +     r = amdgpu_fence_wait_polling(ring,
> +                                   seq - ring->fence_drv.num_fences_mask,
> +                                   timeout);
> +     if (r < 1)
> +             goto error_undo;
> +
>        api_status = (struct MES_API_STATUS *)((char *)pkt + api_status_off);
>        api_status->api_completion_fence_addr = status_gpu_addr;
>        api_status->api_completion_fence_value = 1;
> @@ -208,8 +215,7 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        mes_status_pkt.header.dwsize = API_FRAME_SIZE_IN_DWORDS;
>        mes_status_pkt.api_status.api_completion_fence_addr =
>                ring->fence_drv.gpu_addr;
> -     mes_status_pkt.api_status.api_completion_fence_value =
> -             ++ring->fence_drv.sync_seq;
> +     mes_status_pkt.api_status.api_completion_fence_value = seq;
>
>        amdgpu_ring_write_multiple(ring, &mes_status_pkt,
>                                   sizeof(mes_status_pkt) / 4);
> @@ -229,7 +235,7 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>                dev_dbg(adev->dev, "MES msg=%d was emitted\n",
>                        x_pkt->header.opcode);
>
> -     r = amdgpu_fence_wait_polling(ring, ring->fence_drv.sync_seq, timeout);
> +     r = amdgpu_fence_wait_polling(ring, seq, timeout);
>        if (r < 1 || !*status_ptr) {
>
>                if (misc_op_str)
> @@ -252,6 +258,10 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        amdgpu_device_wb_free(adev, status_offset);
>        return 0;
>
> +error_undo:
> +     dev_err(adev->dev, "MES ring buffer is full.\n");
> +     amdgpu_ring_undo(ring);
> +
>   error_unlock_free:
>        spin_unlock_irqrestore(&mes->ring_lock, flags);
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c b/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
> index c9f74231ad59..48e01206bcc4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
> @@ -154,7 +154,7 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        const char *op_str, *misc_op_str;
>        unsigned long flags;
>        u64 status_gpu_addr;
> -     u32 status_offset;
> +     u32 seq, status_offset;
>        u64 *status_ptr;
>        signed long r;
>        int ret;
> @@ -182,6 +182,13 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        if (r)
>                goto error_unlock_free;
>
> +     seq = ++ring->fence_drv.sync_seq;
> +     r = amdgpu_fence_wait_polling(ring,
> +                                   seq - ring->fence_drv.num_fences_mask,

That's what's amdgpu_fence_emit_polling() does anyway.

So this here just moves the polling a bit earlier.

I think we rather need to increase the MES ring size instead.

Regards,
Christian.


> +                                   timeout);
> +     if (r < 1)
> +             goto error_undo;
> +
>        api_status = (struct MES_API_STATUS *)((char *)pkt + api_status_off);
>        api_status->api_completion_fence_addr = status_gpu_addr;
>        api_status->api_completion_fence_value = 1;
> @@ -194,8 +201,7 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        mes_status_pkt.header.dwsize = API_FRAME_SIZE_IN_DWORDS;
>        mes_status_pkt.api_status.api_completion_fence_addr =
>                ring->fence_drv.gpu_addr;
> -     mes_status_pkt.api_status.api_completion_fence_value =
> -             ++ring->fence_drv.sync_seq;
> +     mes_status_pkt.api_status.api_completion_fence_value = seq;
>
>        amdgpu_ring_write_multiple(ring, &mes_status_pkt,
>                                   sizeof(mes_status_pkt) / 4);
> @@ -215,7 +221,7 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>                dev_dbg(adev->dev, "MES msg=%d was emitted\n",
>                        x_pkt->header.opcode);
>
> -     r = amdgpu_fence_wait_polling(ring, ring->fence_drv.sync_seq, timeout);
> +     r = amdgpu_fence_wait_polling(ring, seq, timeout);
>        if (r < 1 || !*status_ptr) {
>
>                if (misc_op_str)
> @@ -238,6 +244,10 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>        amdgpu_device_wb_free(adev, status_offset);
>        return 0;
>
> +error_undo:
> +     dev_err(adev->dev, "MES ring buffer is full.\n");
> +     amdgpu_ring_undo(ring);
> +
>   error_unlock_free:
>        spin_unlock_irqrestore(&mes->ring_lock, flags);
>


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