drm/amdgpu: Make SDMA phase quantum configurable
Set a configurable SDMA phase quantum when enabling SDMA context
switching. The default value significantly reduces SDMA latency
in page table updates when user-mode SDMA queues have concurrent
activity, compared to the initial HW setting.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Andres Rodriguez <andres.rodriguez@amd.com>
Reviewed-by: Shaoyun Liu <shaoyun.liu@amd.com>
Acked-by: Chunming Zhou <david1.zhou@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index c290b26..ebd077f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -107,6 +107,7 @@ extern unsigned amdgpu_pcie_gen_cap;
extern unsigned amdgpu_pcie_lane_cap;
extern unsigned amdgpu_cg_mask;
extern unsigned amdgpu_pg_mask;
+extern unsigned amdgpu_sdma_phase_quantum;
extern char *amdgpu_disable_cu;
extern char *amdgpu_virtual_display;
extern unsigned amdgpu_pp_feature_mask;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 3c83fe6..b3d7beb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -108,6 +108,7 @@ unsigned amdgpu_pcie_gen_cap = 0;
unsigned amdgpu_pcie_lane_cap = 0;
unsigned amdgpu_cg_mask = 0xffffffff;
unsigned amdgpu_pg_mask = 0xffffffff;
+unsigned amdgpu_sdma_phase_quantum = 32;
char *amdgpu_disable_cu = NULL;
char *amdgpu_virtual_display = NULL;
unsigned amdgpu_pp_feature_mask = 0xffffffff;
@@ -227,6 +228,9 @@ module_param_named(cg_mask, amdgpu_cg_mask, uint, 0444);
MODULE_PARM_DESC(pg_mask, "Powergating flags mask (0 = disable power gating)");
module_param_named(pg_mask, amdgpu_pg_mask, uint, 0444);
+MODULE_PARM_DESC(sdma_phase_quantum, "SDMA context switch phase quantum (x 1K GPU clock cycles, 0 = no change (default 32))");
+module_param_named(sdma_phase_quantum, amdgpu_sdma_phase_quantum, uint, 0444);
+
MODULE_PARM_DESC(disable_cu, "Disable CUs (se.sh.cu,...)");
module_param_named(disable_cu, amdgpu_disable_cu, charp, 0444);
diff --git a/drivers/gpu/drm/amd/amdgpu/cik_sdma.c b/drivers/gpu/drm/amd/amdgpu/cik_sdma.c
index 4a9cea0..f508f4d 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik_sdma.c
@@ -351,14 +351,44 @@ static void cik_sdma_rlc_stop(struct amdgpu_device *adev)
*/
static void cik_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
{
- u32 f32_cntl;
+ u32 f32_cntl, phase_quantum = 0;
int i;
+ if (amdgpu_sdma_phase_quantum) {
+ unsigned value = amdgpu_sdma_phase_quantum;
+ unsigned unit = 0;
+
+ while (value > (SDMA0_PHASE0_QUANTUM__VALUE_MASK >>
+ SDMA0_PHASE0_QUANTUM__VALUE__SHIFT)) {
+ value = (value + 1) >> 1;
+ unit++;
+ }
+ if (unit > (SDMA0_PHASE0_QUANTUM__UNIT_MASK >>
+ SDMA0_PHASE0_QUANTUM__UNIT__SHIFT)) {
+ value = (SDMA0_PHASE0_QUANTUM__VALUE_MASK >>
+ SDMA0_PHASE0_QUANTUM__VALUE__SHIFT);
+ unit = (SDMA0_PHASE0_QUANTUM__UNIT_MASK >>
+ SDMA0_PHASE0_QUANTUM__UNIT__SHIFT);
+ WARN_ONCE(1,
+ "clamping sdma_phase_quantum to %uK clock cycles\n",
+ value << unit);
+ }
+ phase_quantum =
+ value << SDMA0_PHASE0_QUANTUM__VALUE__SHIFT |
+ unit << SDMA0_PHASE0_QUANTUM__UNIT__SHIFT;
+ }
+
for (i = 0; i < adev->sdma.num_instances; i++) {
f32_cntl = RREG32(mmSDMA0_CNTL + sdma_offsets[i]);
if (enable) {
f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
AUTO_CTXSW_ENABLE, 1);
+ if (amdgpu_sdma_phase_quantum) {
+ WREG32(mmSDMA0_PHASE0_QUANTUM + sdma_offsets[i],
+ phase_quantum);
+ WREG32(mmSDMA0_PHASE1_QUANTUM + sdma_offsets[i],
+ phase_quantum);
+ }
} else {
f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
AUTO_CTXSW_ENABLE, 0);
diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c b/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c
index 67a29fb..b1de44f 100644
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c
@@ -551,9 +551,33 @@ static void sdma_v3_0_rlc_stop(struct amdgpu_device *adev)
*/
static void sdma_v3_0_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
{
- u32 f32_cntl;
+ u32 f32_cntl, phase_quantum = 0;
int i;
+ if (amdgpu_sdma_phase_quantum) {
+ unsigned value = amdgpu_sdma_phase_quantum;
+ unsigned unit = 0;
+
+ while (value > (SDMA0_PHASE0_QUANTUM__VALUE_MASK >>
+ SDMA0_PHASE0_QUANTUM__VALUE__SHIFT)) {
+ value = (value + 1) >> 1;
+ unit++;
+ }
+ if (unit > (SDMA0_PHASE0_QUANTUM__UNIT_MASK >>
+ SDMA0_PHASE0_QUANTUM__UNIT__SHIFT)) {
+ value = (SDMA0_PHASE0_QUANTUM__VALUE_MASK >>
+ SDMA0_PHASE0_QUANTUM__VALUE__SHIFT);
+ unit = (SDMA0_PHASE0_QUANTUM__UNIT_MASK >>
+ SDMA0_PHASE0_QUANTUM__UNIT__SHIFT);
+ WARN_ONCE(1,
+ "clamping sdma_phase_quantum to %uK clock cycles\n",
+ value << unit);
+ }
+ phase_quantum =
+ value << SDMA0_PHASE0_QUANTUM__VALUE__SHIFT |
+ unit << SDMA0_PHASE0_QUANTUM__UNIT__SHIFT;
+ }
+
for (i = 0; i < adev->sdma.num_instances; i++) {
f32_cntl = RREG32(mmSDMA0_CNTL + sdma_offsets[i]);
if (enable) {
@@ -561,6 +585,12 @@ static void sdma_v3_0_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
AUTO_CTXSW_ENABLE, 1);
f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
ATC_L1_ENABLE, 1);
+ if (amdgpu_sdma_phase_quantum) {
+ WREG32(mmSDMA0_PHASE0_QUANTUM + sdma_offsets[i],
+ phase_quantum);
+ WREG32(mmSDMA0_PHASE1_QUANTUM + sdma_offsets[i],
+ phase_quantum);
+ }
} else {
f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
AUTO_CTXSW_ENABLE, 0);
diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c b/drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c
index 4a65697..591f3e7 100644
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c
@@ -493,13 +493,45 @@ static void sdma_v4_0_rlc_stop(struct amdgpu_device *adev)
*/
static void sdma_v4_0_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
{
- u32 f32_cntl;
+ u32 f32_cntl, phase_quantum = 0;
int i;
+ if (amdgpu_sdma_phase_quantum) {
+ unsigned value = amdgpu_sdma_phase_quantum;
+ unsigned unit = 0;
+
+ while (value > (SDMA0_PHASE0_QUANTUM__VALUE_MASK >>
+ SDMA0_PHASE0_QUANTUM__VALUE__SHIFT)) {
+ value = (value + 1) >> 1;
+ unit++;
+ }
+ if (unit > (SDMA0_PHASE0_QUANTUM__UNIT_MASK >>
+ SDMA0_PHASE0_QUANTUM__UNIT__SHIFT)) {
+ value = (SDMA0_PHASE0_QUANTUM__VALUE_MASK >>
+ SDMA0_PHASE0_QUANTUM__VALUE__SHIFT);
+ unit = (SDMA0_PHASE0_QUANTUM__UNIT_MASK >>
+ SDMA0_PHASE0_QUANTUM__UNIT__SHIFT);
+ WARN_ONCE(1,
+ "clamping sdma_phase_quantum to %uK clock cycles\n",
+ value << unit);
+ }
+ phase_quantum =
+ value << SDMA0_PHASE0_QUANTUM__VALUE__SHIFT |
+ unit << SDMA0_PHASE0_QUANTUM__UNIT__SHIFT;
+ }
+
for (i = 0; i < adev->sdma.num_instances; i++) {
f32_cntl = RREG32(sdma_v4_0_get_reg_offset(i, mmSDMA0_CNTL));
f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
AUTO_CTXSW_ENABLE, enable ? 1 : 0);
+ if (enable && amdgpu_sdma_phase_quantum) {
+ WREG32(sdma_v4_0_get_reg_offset(i, mmSDMA0_PHASE0_QUANTUM),
+ phase_quantum);
+ WREG32(sdma_v4_0_get_reg_offset(i, mmSDMA0_PHASE1_QUANTUM),
+ phase_quantum);
+ WREG32(sdma_v4_0_get_reg_offset(i, mmSDMA0_PHASE2_QUANTUM),
+ phase_quantum);
+ }
WREG32(sdma_v4_0_get_reg_offset(i, mmSDMA0_CNTL), f32_cntl);
}