Re: [PATCH] drm/amdgpu: Add graphics cache rinse packet for sdma 5.0

From: Alex Deucher <alexdeucher@gmail.com>
To: Alex Deucher <alexander.deucher@amd.com>
Cc: amd-gfx list <amd-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] drm/amdgpu: Add graphics cache rinse packet for sdma 5.0
Date: Wed, 28 Apr 2021 23:40:57 -0400	[thread overview]
Message-ID: <CADnq5_O7OWgmX72VBOqSYKkq=A0dVmxGFmg9om54HCqen0r5EA@mail.gmail.com> (raw)
In-Reply-To: <20210420192739.1906700-1-alexander.deucher@amd.com>

Ping?

On Tue, Apr 20, 2021 at 3:28 PM Alex Deucher <alexander.deucher@amd.com> wrote:
>
> Add emit mem sync callback for sdma_v5_0
>
> In amdgpu sync object test, three threads created jobs
> to send GFX IB and SDMA IB in sequence. After the first
> GFX thread joined, sometimes the third thread will reuse
> the same physical page to store the SDMA IB. There will
> be a risk that SDMA will read GFX IB in the previous physical
> page. So it's better to flush the cache before commit sdma IB.
>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c | 28 ++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
> index 920fc6d4a127..d294ef6a625a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c
> @@ -437,6 +437,33 @@ static void sdma_v5_0_ring_emit_ib(struct amdgpu_ring *ring,
>         amdgpu_ring_write(ring, upper_32_bits(csa_mc_addr));
>  }
>
> +/**
> + * sdma_v5_0_ring_emit_mem_sync - flush the IB by graphics cache rinse
> + *
> + * @ring: amdgpu ring pointer
> + * @job: job to retrieve vmid from
> + * @ib: IB object to schedule
> + *
> + * flush the IB by graphics cache rinse.
> + */
> +static void sdma_v5_0_ring_emit_mem_sync(struct amdgpu_ring *ring)
> +{
> +    uint32_t gcr_cntl =
> +                   SDMA_GCR_GL2_INV | SDMA_GCR_GL2_WB | SDMA_GCR_GLM_INV |
> +                       SDMA_GCR_GL1_INV | SDMA_GCR_GLV_INV | SDMA_GCR_GLK_INV |
> +                       SDMA_GCR_GLI_INV(1);
> +
> +       /* flush entire cache L0/L1/L2, this can be optimized by performance requirement */
> +       amdgpu_ring_write(ring, SDMA_PKT_HEADER_OP(SDMA_OP_GCR_REQ));
> +       amdgpu_ring_write(ring, SDMA_PKT_GCR_REQ_PAYLOAD1_BASE_VA_31_7(0));
> +       amdgpu_ring_write(ring, SDMA_PKT_GCR_REQ_PAYLOAD2_GCR_CONTROL_15_0(gcr_cntl) |
> +                       SDMA_PKT_GCR_REQ_PAYLOAD2_BASE_VA_47_32(0));
> +       amdgpu_ring_write(ring, SDMA_PKT_GCR_REQ_PAYLOAD3_LIMIT_VA_31_7(0) |
> +                       SDMA_PKT_GCR_REQ_PAYLOAD3_GCR_CONTROL_18_16(gcr_cntl >> 16));
> +       amdgpu_ring_write(ring, SDMA_PKT_GCR_REQ_PAYLOAD4_LIMIT_VA_47_32(0) |
> +                       SDMA_PKT_GCR_REQ_PAYLOAD4_VMID(0));
> +}
> +
>  /**
>   * sdma_v5_0_ring_emit_hdp_flush - emit an hdp flush on the DMA ring
>   *
> @@ -1643,6 +1670,7 @@ static const struct amdgpu_ring_funcs sdma_v5_0_ring_funcs = {
>                 10 + 10 + 10, /* sdma_v5_0_ring_emit_fence x3 for user fence, vm fence */
>         .emit_ib_size = 5 + 7 + 6, /* sdma_v5_0_ring_emit_ib */
>         .emit_ib = sdma_v5_0_ring_emit_ib,
> +       .emit_mem_sync = sdma_v5_0_ring_emit_mem_sync,
>         .emit_fence = sdma_v5_0_ring_emit_fence,
>         .emit_pipeline_sync = sdma_v5_0_ring_emit_pipeline_sync,
>         .emit_vm_flush = sdma_v5_0_ring_emit_vm_flush,
> --
> 2.30.2
>
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