[PATCH 4/4] drm/i915/selftests: Split RPS frequency measurement
Chris Wilson
chris at chris-wilson.co.uk
Sun Apr 19 11:17:33 UTC 2020
Split the frequency measurement into two modes, so that we can judge the
impact of the llc setup on top of the pure CS frequency scaling.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gt/selftest_gt_pm.c | 3 +-
drivers/gpu/drm/i915/gt/selftest_rps.c | 157 ++++++++++++++++++++++-
drivers/gpu/drm/i915/gt/selftest_rps.h | 3 +-
3 files changed, 154 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
index de3eaef40596..9855e6f0ce7c 100644
--- a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
@@ -54,7 +54,8 @@ int intel_gt_pm_live_selftests(struct drm_i915_private *i915)
static const struct i915_subtest tests[] = {
SUBTEST(live_rc6_manual),
SUBTEST(live_rps_control),
- SUBTEST(live_rps_frequency),
+ SUBTEST(live_rps_frequency_cs),
+ SUBTEST(live_rps_frequency_srm),
SUBTEST(live_rps_power),
SUBTEST(live_rps_interrupt),
SUBTEST(live_gt_resume),
diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
index 19fa6a561de3..dbca673519a2 100644
--- a/drivers/gpu/drm/i915/gt/selftest_rps.c
+++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
@@ -33,6 +33,7 @@ static int cmp_u64(const void *A, const void *B)
static struct i915_vma *
create_spin_counter(struct intel_engine_cs *engine,
struct i915_address_space *vm,
+ bool srm,
u32 **cancel,
u32 **counter)
{
@@ -91,10 +92,12 @@ create_spin_counter(struct intel_engine_cs *engine,
*cs++ = MI_MATH_ADD;
*cs++ = MI_MATH_STORE(MI_MATH_REG(COUNT), MI_MATH_REG_ACCU);
- *cs++ = MI_STORE_REGISTER_MEM_GEN8;
- *cs++ = i915_mmio_reg_offset(CS_GPR(COUNT));
- *cs++ = lower_32_bits(vma->node.start + 1000 * sizeof(*cs));
- *cs++ = upper_32_bits(vma->node.start + 1000 * sizeof(*cs));
+ if (srm) {
+ *cs++ = MI_STORE_REGISTER_MEM_GEN8;
+ *cs++ = i915_mmio_reg_offset(CS_GPR(COUNT));
+ *cs++ = lower_32_bits(vma->node.start + 1000 * sizeof(*cs));
+ *cs++ = upper_32_bits(vma->node.start + 1000 * sizeof(*cs));
+ }
*cs++ = MI_BATCH_BUFFER_START_GEN8;
*cs++ = lower_32_bits(vma->node.start + loop * sizeof(*cs));
@@ -103,7 +106,7 @@ create_spin_counter(struct intel_engine_cs *engine,
i915_gem_object_flush_map(obj);
*cancel = base + loop;
- *counter = memset32(base + 1000, 0, 1);
+ *counter = srm ? memset32(base + 1000, 0, 1) : NULL;
return vma;
}
@@ -301,12 +304,152 @@ static u64 measure_frequency_at(struct intel_rps *rps, u32 *cntr, int *freq)
return div_u64(x[1] + 2 * x[2] + x[3], 4);
}
+static u64 __measure_cs_frequency(struct intel_engine_cs *engine,
+ int duration_ms)
+{
+ u64 dc, dt;
+
+ dt = ktime_get();
+ dc = intel_uncore_read_fw(engine->uncore, CS_GPR(0));
+ usleep_range(1000 * duration_ms, 2000 * duration_ms);
+ dc = intel_uncore_read_fw(engine->uncore, CS_GPR(0)) - dc;
+ dt = ktime_get() - dt;
+
+ return div64_u64(1000 * 1000 * dc, dt);
+}
+
+static u64 measure_cs_frequency_at(struct intel_rps *rps,
+ struct intel_engine_cs *engine,
+ int *freq)
+{
+ u64 x[5];
+ int i;
+
+ *freq = rps_set_check(rps, *freq);
+ for (i = 0; i < 5; i++)
+ x[i] = __measure_cs_frequency(engine, 2);
+ *freq = (*freq + read_cagf(rps)) / 2;
+
+ /* A simple triangle filter for better result stability */
+ sort(x, 5, sizeof(*x), cmp_u64, NULL);
+ return div_u64(x[1] + 2 * x[2] + x[3], 4);
+}
+
static bool scaled_within(u64 x, u64 y, u32 f_n, u32 f_d)
{
return f_d * x > f_n * y && f_n * x < f_d * y;
}
-int live_rps_frequency(void *arg)
+int live_rps_frequency_cs(void *arg)
+{
+ void (*saved_work)(struct work_struct *wrk);
+ struct intel_gt *gt = arg;
+ struct intel_rps *rps = >->rps;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ int err = 0;
+
+ /*
+ * The premise is that the GPU does change freqency at our behest.
+ * Let's check there is a correspondence between the requested
+ * frequency, the actual frequency, and the observed clock rate.
+ */
+
+ if (!rps->enabled || rps->max_freq <= rps->min_freq)
+ return 0;
+
+ if (INTEL_GEN(gt->i915) < 8) /* for CS simplicity */
+ return 0;
+
+ intel_gt_pm_wait_for_idle(gt);
+ saved_work = rps->work.func;
+ rps->work.func = dummy_rps_work;
+
+ for_each_engine(engine, gt, id) {
+ struct i915_request *rq;
+ struct i915_vma *vma;
+ u32 *cancel, *cntr;
+ struct {
+ u64 count;
+ int freq;
+ } min, max;
+
+ vma = create_spin_counter(engine,
+ engine->kernel_context->vm, false,
+ &cancel, &cntr);
+ if (IS_ERR(vma)) {
+ err = PTR_ERR(vma);
+ break;
+ }
+
+ rq = intel_engine_create_kernel_request(engine);
+ if (IS_ERR(rq)) {
+ err = PTR_ERR(rq);
+ goto err_vma;
+ }
+
+ i915_vma_lock(vma);
+ err = i915_request_await_object(rq, vma->obj, false);
+ if (!err)
+ err = i915_vma_move_to_active(vma, rq, 0);
+ if (!err)
+ err = rq->engine->emit_bb_start(rq,
+ vma->node.start,
+ PAGE_SIZE, 0);
+ i915_vma_unlock(vma);
+ i915_request_add(rq);
+ if (err)
+ goto err_vma;
+
+ if (wait_for(intel_uncore_read(engine->uncore, CS_GPR(0)),
+ 10)) {
+ pr_err("%s: timed loop did not start\n",
+ engine->name);
+ goto err_vma;
+ }
+
+ min.freq = rps->min_freq;
+ min.count = measure_cs_frequency_at(rps, engine, &min.freq);
+
+ max.freq = rps->max_freq;
+ max.count = measure_cs_frequency_at(rps, engine, &max.freq);
+
+ pr_info("%s: min:%lluKHz @ %uMHz, max:%lluKHz @ %uMHz [%d%%]\n",
+ engine->name,
+ min.count, intel_gpu_freq(rps, min.freq),
+ max.count, intel_gpu_freq(rps, max.freq),
+ (int)DIV64_U64_ROUND_CLOSEST(100 * min.freq * max.count,
+ max.freq * min.count));
+
+ if (!scaled_within(max.freq * min.count,
+ min.freq * max.count,
+ 2, 3)) {
+ pr_err("%s: CS did not scale with frequency! scaled min:%llu, max:%llu\n",
+ engine->name,
+ max.freq * min.count,
+ min.freq * max.count);
+ err = -EINVAL;
+ }
+
+err_vma:
+ *cancel = MI_BATCH_BUFFER_END;
+ i915_gem_object_unpin_map(vma->obj);
+ i915_vma_unpin(vma);
+ i915_vma_put(vma);
+
+ if (igt_flush_test(gt->i915))
+ err = -EIO;
+ if (err)
+ break;
+ }
+
+ intel_gt_pm_wait_for_idle(gt);
+ rps->work.func = saved_work;
+
+ return err;
+}
+
+int live_rps_frequency_srm(void *arg)
{
void (*saved_work)(struct work_struct *wrk);
struct intel_gt *gt = arg;
@@ -341,7 +484,7 @@ int live_rps_frequency(void *arg)
} min, max;
vma = create_spin_counter(engine,
- engine->kernel_context->vm,
+ engine->kernel_context->vm, true,
&cancel, &cntr);
if (IS_ERR(vma)) {
err = PTR_ERR(vma);
diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.h b/drivers/gpu/drm/i915/gt/selftest_rps.h
index be0bf8e3f639..22e46c5341c5 100644
--- a/drivers/gpu/drm/i915/gt/selftest_rps.h
+++ b/drivers/gpu/drm/i915/gt/selftest_rps.h
@@ -7,7 +7,8 @@
#define SELFTEST_RPS_H
int live_rps_control(void *arg);
-int live_rps_frequency(void *arg);
+int live_rps_frequency_cs(void *arg);
+int live_rps_frequency_srm(void *arg);
int live_rps_interrupt(void *arg);
int live_rps_power(void *arg);
--
2.20.1
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