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drm/amdgpu: Read clock counter via MMIO to reduce delay (v5)

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[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.Wang@amd.com>
Acked-by: Horace Chen <horace.chen@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.co>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
YuBiao Wang 2021-06-29 11:21:25 +08:00 • committed by Alex Deucher
parent 51627f0380
commit 5af4438f1e
1 changed files with 14 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

21
drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
View file

@ -7605,10 +7605,8 @@ 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:
@ -7616,12 +7614,21 @@ 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);
preempt_disable();
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 SMUIO TSC clock frequency is 100MHz, which sets 32-bit carry over
* roughly every 42 seconds.
*/
if (hi_check != clock_hi) {
clock_lo = RREG32_SOC15_NO_KIQ(SMUIO, 0, mmGOLDEN_TSC_COUNT_LOWER);
clock_hi = hi_check;
}
preempt_enable();
clock = clock_lo | (clock_hi << 32ULL);
break;
}
mutex_unlock(&adev->gfx.gpu_clock_mutex);
amdgpu_gfx_off_ctrl(adev, true);
return clock;
}