[AMD Official Use Only]
reviewed-by: Monk Liu <monk.liu@xxxxxxx>
Thanks
------------------------------------------
Monk Liu | Cloud-GPU Core team
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-----Original Message-----
From: YuBiao Wang <YuBiao.Wang@xxxxxxx>
Sent: Wednesday, June 30, 2021 6:10 PM
To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>; Quan, Evan <Evan.Quan@xxxxxxx>; Chen, Horace <Horace.Chen@xxxxxxx>; Tuikov, Luben <Luben.Tuikov@xxxxxxx>; Koenig, Christian <Christian.Koenig@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Xiao, Jack <Jack.Xiao@xxxxxxx>; Zhang, Hawking <Hawking.Zhang@xxxxxxx>; Liu, Monk <Monk.Liu@xxxxxxx>; Xu, Feifei <Feifei.Xu@xxxxxxx>; Wang, Kevin(Yang) <Kevin1.Wang@xxxxxxx>; Wang, YuBiao <YuBiao.Wang@xxxxxxx>
Subject: [PATCH 1/1] drm/amdgpu: Read clock counter via MMIO to reduce delay (v4)
[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.
Signed-off-by: YuBiao Wang <YuBiao.Wang@xxxxxxx>
Acked-by: Horace Chen <horace.chen@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 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..9355494002a1 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
@@ -7609,7 +7609,7 @@ 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);
@@ -7620,8 +7620,15 @@ 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);
+ /* Carryover happens every 4 Giga time cycles counts which is roughly 42 secs */
+ if (hi_check != clock_hi) {
+ 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);
--
2.25.1
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