On 2021-07-01 5:57 a.m., YuBiao Wang wrote:
> [Why]
> GPU timing counters are read via KIQ under sriov, which will introduce
> a delay.
>
> [How]
> It could be directly read by MMIO.
>
> v2: Add additional check to prevent carryover issue.
> v3: Only check for carryover for once to prevent performance issue.
> v4: Add comments of the rough frequency where carryover happens.
> v5: Remove mutex and gfxoff ctrl unused with current timing registers.
>
> Signed-off-by: YuBiao Wang <yubiao.w...@amd.com>
> Acked-by: Horace Chen <horace.c...@amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
> b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
> index ff7e9f49040e..5f4eae9c9526 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
> @@ -7609,10 +7609,8 @@ static int gfx_v10_0_soft_reset(void *handle)
>
> static uint64_t gfx_v10_0_get_gpu_clock_counter(struct amdgpu_device *adev)
> {
> - uint64_t clock;
> + uint64_t clock, clock_lo, clock_hi, hi_check;
>
> - amdgpu_gfx_off_ctrl(adev, false);
> - mutex_lock(&adev->gfx.gpu_clock_mutex);
> switch (adev->asic_type) {
> case CHIP_VANGOGH:
> case CHIP_YELLOW_CARP:
> @@ -7620,12 +7618,19 @@ static uint64_t
> gfx_v10_0_get_gpu_clock_counter(struct amdgpu_device *adev)
> ((uint64_t)RREG32_SOC15(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_UPPER_Vangogh) << 32ULL);
> break;
> default:
> - clock = (uint64_t)RREG32_SOC15(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_LOWER) |
> - ((uint64_t)RREG32_SOC15(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_UPPER) << 32ULL);
> + clock_hi = RREG32_SOC15_NO_KIQ(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_UPPER);
> + clock_lo = RREG32_SOC15_NO_KIQ(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_LOWER);
> + hi_check = RREG32_SOC15_NO_KIQ(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_UPPER);
> + /* The GFX clock frequency is 100MHz, which sets 32-bit carry
> over
> + * roughly every 42 seconds.
> + */
> + if (hi_check != clock_hi) {
Yeah, the comment is so much better now. Good job.
Reviewed-by: Luben Tuikov <luben.tui...@amd.com>
Regards,
Luben
> + clock_lo = RREG32_SOC15_NO_KIQ(SMUIO, 0,
> mmGOLDEN_TSC_COUNT_LOWER);
> + clock_hi = hi_check;
> + }
> + clock = (uint64_t)clock_lo | ((uint64_t)clock_hi << 32ULL);
> break;
> }
> - mutex_unlock(&adev->gfx.gpu_clock_mutex);
> - amdgpu_gfx_off_ctrl(adev, true);
> return clock;
> }
>
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