[Intel-gfx] [PATCH] drm/i915/gt: Fix up clock frequency
Mika Kuoppala
mika.kuoppala at linux.intel.com
Mon Apr 27 12:15:23 UTC 2020
Chris Wilson <chris at chris-wilson.co.uk> writes:
> The bspec lists both the clock frequency and the effective interval. The
> interval corresponds to observed behaviour, so adjust the frequency to
> match.
>
> v2: Mika rightfully asked if we could measure the clock frequency from a
> selftest.
This kind of delivery times might impact on demand :P
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> ---
> .../gpu/drm/i915/gt/intel_gt_clock_utils.c | 12 +-
> drivers/gpu/drm/i915/gt/selftest_gt_pm.c | 1 +
> drivers/gpu/drm/i915/gt/selftest_rps.c | 125 ++++++++++++++++++
> drivers/gpu/drm/i915/gt/selftest_rps.h | 1 +
> 4 files changed, 133 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> index 852a7d731b3b..999079686846 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> @@ -7,9 +7,9 @@
> #include "intel_gt.h"
> #include "intel_gt_clock_utils.h"
>
> +#define MHZ_12 12000000 /* 12MHz (24MHz/2), 83.333ns */
> +#define MHZ_12_5 12500000 /* 12.5MHz (25MHz/2), 80ns */
> #define MHZ_19_2 19200000 /* 19.2MHz, 52.083ns */
> -#define MHZ_24 24000000 /* 24MHz, 83.333ns */
> -#define MHZ_25 25000000 /* 25MHz, 80ns */
>
> static u32 read_clock_frequency(const struct intel_gt *gt)
> {
> @@ -21,19 +21,19 @@ static u32 read_clock_frequency(const struct intel_gt *gt)
> config >>= GEN11_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_SHIFT;
>
> switch (config) {
> - case 0: return MHZ_24;
> + case 0: return MHZ_12;
> case 1:
> case 2: return MHZ_19_2;
> default:
> - case 3: return MHZ_25;
> + case 3: return MHZ_12_5;
> }
> } else if (INTEL_GEN(gt->i915) >= 9) {
> if (IS_GEN9_LP(gt->i915))
> return MHZ_19_2;
> else
> - return MHZ_24;
> + return MHZ_12;
> } else {
> - return MHZ_25;
> + return MHZ_12_5;
> }
> }
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
> index e02fdec58826..242181a5214c 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
> @@ -53,6 +53,7 @@ int intel_gt_pm_live_selftests(struct drm_i915_private *i915)
> {
> static const struct i915_subtest tests[] = {
> SUBTEST(live_rc6_manual),
> + SUBTEST(live_rps_clock_interval),
> SUBTEST(live_rps_control),
> SUBTEST(live_rps_frequency_cs),
> SUBTEST(live_rps_frequency_srm),
> diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
> index e13cbcb82825..fe92c55572c1 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_rps.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
> @@ -208,6 +208,131 @@ static void show_pstate_limits(struct intel_rps *rps)
> }
> }
>
> +int live_rps_clock_interval(void *arg)
> +{
> + struct intel_gt *gt = arg;
> + struct intel_rps *rps = >->rps;
> + void (*saved_work)(struct work_struct *wrk);
> + struct intel_engine_cs *engine;
> + enum intel_engine_id id;
> + struct igt_spinner spin;
> + int err = 0;
> +
> + if (!rps->enabled)
> + return 0;
> +
> + intel_gt_check_clock_frequency(gt);
> +
> + if (igt_spinner_init(&spin, gt))
> + return -ENOMEM;
> +
> + intel_gt_pm_wait_for_idle(gt);
> + saved_work = rps->work.func;
> + rps->work.func = dummy_rps_work;
> +
> + intel_gt_pm_get(gt);
> + intel_rps_disable(>->rps);
> +
> + for_each_engine(engine, gt, id) {
> + unsigned long saved_heartbeat;
> + struct i915_request *rq;
> + u32 cycles, expected;
> + ktime_t dt;
> + u64 time;
> +
> + if (!intel_engine_can_store_dword(engine))
> + continue;
> +
> + saved_heartbeat = engine_heartbeat_disable(engine);
> +
> + rq = igt_spinner_create_request(&spin,
> + engine->kernel_context,
> + MI_NOOP);
> + if (IS_ERR(rq)) {
> + err = PTR_ERR(rq);
> + break;
> + }
> +
> + i915_request_add(rq);
> +
> + if (!igt_wait_for_spinner(&spin, rq)) {
> + pr_err("%s: RPS spinner did not start\n",
> + engine->name);
> + igt_spinner_end(&spin);
> + engine_heartbeat_enable(engine, saved_heartbeat);
> + intel_gt_set_wedged(engine->gt);
> + err = -EIO;
> + break;
> + }
> +
> + intel_uncore_write(gt->uncore, GEN6_RP_CUR_UP_EI, 0);
> +
> + /* Set the evaluation interval to infinity! */
> + intel_uncore_write(gt->uncore,
> + GEN6_RP_UP_EI, 0xffffffff);
> + intel_uncore_write(gt->uncore,
> + GEN6_RP_UP_THRESHOLD, 0xffffffff);
To keep it constant during the calculation?
> +
> + intel_uncore_write(gt->uncore, GEN6_RP_CONTROL,
> + GEN6_RP_ENABLE | GEN6_RP_UP_BUSY_AVG);
> +
> + if (wait_for(intel_uncore_read(gt->uncore, GEN6_RP_CUR_UP_EI),
> + 10)) {
> + pr_err("%s: rps evalution interval not ticking\n",
> + engine->name);
> + igt_spinner_end(&spin);
> + engine_heartbeat_enable(engine, saved_heartbeat);
> + err = -ENODEV;
> + break;
> + }
> +
> + dt = ktime_get();
> + cycles = -intel_uncore_read(gt->uncore, GEN6_RP_CUR_UP_EI);
Hmm you have not zeroed the cycles on the first run, but does it matter
is then the question.
-Mika
> + usleep_range(1000, 2000);
> + dt = ktime_sub(ktime_get(), dt);
> + cycles += intel_uncore_read(gt->uncore, GEN6_RP_CUR_UP_EI);
> +
> + intel_uncore_write(gt->uncore, GEN6_RP_CONTROL, 0);
> +
> + igt_spinner_end(&spin);
> + engine_heartbeat_enable(engine, saved_heartbeat);
> +
> + time = intel_gt_pm_interval_to_ns(gt, cycles);
> + expected = intel_gt_ns_to_pm_interval(gt, ktime_to_ns(dt));
> + pr_info("%s: rps counted %d C0 cycles [%lldns] in %lldns [%d cycles], using GT clock frequency of %uKHz\n",
> + engine->name, cycles, time, ktime_to_ns(dt), expected,
> + gt->clock_frequency / 1000);
> +
> + if (10 * time < 9 * ktime_to_ns(dt) ||
> + 10 * time > 11 * ktime_to_ns(dt)) {
> + pr_err("%s: rps clock time does not match walltime!\n",
> + engine->name);
> + err = -EINVAL;
> + }
> +
> + if (10 * expected < 9 * cycles || 10 * expected > 11 * cycles) {
> + pr_err("%s: walltime does not match rps clock ticks!\n",
> + engine->name);
> + err = -EINVAL;
> + }
> +
> + if (igt_flush_test(gt->i915))
> + err = -EIO;
> +
> + break; /* once is enough */
> + }
> +
> + intel_rps_enable(>->rps);
> + intel_gt_pm_put(gt);
> +
> + igt_spinner_fini(&spin);
> +
> + intel_gt_pm_wait_for_idle(gt);
> + rps->work.func = saved_work;
> +
> + return err;
> +}
> +
> int live_rps_control(void *arg)
> {
> struct intel_gt *gt = arg;
> diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.h b/drivers/gpu/drm/i915/gt/selftest_rps.h
> index 76c4b19553e6..6e82a631cfa1 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_rps.h
> +++ b/drivers/gpu/drm/i915/gt/selftest_rps.h
> @@ -7,6 +7,7 @@
> #define SELFTEST_RPS_H
>
> int live_rps_control(void *arg);
> +int live_rps_clock_interval(void *arg);
> int live_rps_frequency_cs(void *arg);
> int live_rps_frequency_srm(void *arg);
> int live_rps_power(void *arg);
> --
> 2.20.1
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