[Intel-gfx] [PATCH i-g-t] test/i915_pm_rc6_residency: Check we enter RC6 when mostly idle
Imre Deak
imre.deak at intel.com
Fri Jan 10 16:16:27 UTC 2020
On Thu, Jan 09, 2020 at 10:23:00PM +0000, Chris Wilson wrote:
> Long ago, we would only approach runtime-suspend if the GPU had been
> idle (no userspace submissions) for a second or two. However, since
> disabling automatic HW RC6 such a relaxed approach to runtime-suspend
> caused us to never enter RC6 on the desktop and consume vast quantities
> of power. Surmise this behaviour by setting up a background load that is
> only active for ~1% of the time (so equivalent to a compositor that is
> updating the clock every 50ms or so) and verify that we do continue to
> enter RC6 between the GPU pulses.
>
> References: https://gitlab.freedesktop.org/drm/intel/issues/614
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Imre Deak <imre.deak at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
> tests/Makefile.am | 1 +
> tests/i915/i915_pm_rc6_residency.c | 174 +++++++++++++++++++++++++++--
> tests/meson.build | 9 +-
> 3 files changed, 173 insertions(+), 11 deletions(-)
>
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 9a320bc23..fc3052475 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -122,6 +122,7 @@ gem_threaded_access_tiled_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
> gem_threaded_access_tiled_LDADD = $(LDADD) -lpthread
> gem_tiled_swapping_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
> gem_tiled_swapping_LDADD = $(LDADD) -lpthread
> +i915_pm_rc6_residency_LDADD = $(LDADD) $(top_builddir)/lib/libigt_perf.la
> prime_self_import_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
> prime_self_import_LDADD = $(LDADD) -lpthread
> gem_userptr_blits_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
> diff --git a/tests/i915/i915_pm_rc6_residency.c b/tests/i915/i915_pm_rc6_residency.c
> index 1b39c870e..a5bcb084b 100644
> --- a/tests/i915/i915_pm_rc6_residency.c
> +++ b/tests/i915/i915_pm_rc6_residency.c
> @@ -25,8 +25,6 @@
> *
> */
>
> -#include "igt.h"
> -#include "igt_sysfs.h"
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> @@ -34,6 +32,9 @@
> #include <errno.h>
> #include <time.h>
>
> +#include "igt.h"
> +#include "igt_perf.h"
> +#include "igt_sysfs.h"
>
> #define SLEEP_DURATION 3 /* in seconds */
>
> @@ -195,31 +196,180 @@ static bool wait_for_rc6(void)
> return false;
> }
>
> +static uint64_t __pmu_read_single(int fd, uint64_t *ts)
> +{
> + uint64_t data[2];
> +
> + igt_assert_eq(read(fd, data, sizeof(data)), sizeof(data));
> +
> + if (ts)
> + *ts = data[1];
> +
> + return data[0];
> +}
> +
> +static uint64_t pmu_read_single(int fd)
> +{
> + return __pmu_read_single(fd, NULL);
> +}
> +
> +#define __assert_within_epsilon(x, ref, tol_up, tol_down) \
> + igt_assert_f((double)(x) <= (1.0 + (tol_up)) * (double)(ref) && \
> + (double)(x) >= (1.0 - (tol_down)) * (double)(ref), \
> + "'%s' != '%s' (%f not within +%.1f%%/-%.1f%% tolerance of %f)\n",\
> + #x, #ref, (double)(x), \
> + (tol_up) * 100.0, (tol_down) * 100.0, \
> + (double)(ref))
> +
> +#define assert_within_epsilon(x, ref, tolerance) \
> + __assert_within_epsilon(x, ref, tolerance, tolerance)
> +
> +static bool __pmu_wait_for_rc6(int fd)
> +{
> + struct timespec tv = {};
> + uint64_t start, now;
> +
> + /* First wait for roughly an RC6 Evaluation Interval */
> + usleep(160 * 1000);
> +
> + /* Then poll for RC6 to start ticking */
> + now = pmu_read_single(fd);
> + do {
> + start = now;
> + usleep(5000);
> + now = pmu_read_single(fd);
> + if (now - start > 1e6)
> + return true;
> + } while (!igt_seconds_elapsed(&tv));
> +
> + return false;
> +}
> +
> +static unsigned int measured_usleep(unsigned int usec)
> +{
> + struct timespec ts = { };
> + unsigned int slept;
> +
> + slept = igt_nsec_elapsed(&ts);
> + igt_assert(slept == 0);
> + do {
> + usleep(usec - slept);
> + slept = igt_nsec_elapsed(&ts) / 1000;
> + } while (slept < usec);
> +
> + return igt_nsec_elapsed(&ts);
> +}
> +
> +static uint32_t batch_create(int fd)
> +{
> + const uint32_t bbe = MI_BATCH_BUFFER_END;
> + uint32_t handle;
> +
> + handle = gem_create(fd, 4096);
> + gem_write(fd, handle, 0, &bbe, sizeof(bbe));
> +
> + return handle;
> +}
> +
> +static int open_pmu(int i915, uint64_t config)
> +{
> + int fd;
> +
> + fd = perf_i915_open(config);
> + igt_skip_on(fd < 0 && errno == ENODEV);
> + igt_assert(fd >= 0);
> +
> + return fd;
> +}
> +
> +static void rc6_perf(int i915)
> +{
> + const int64_t duration_ns = 2e9;
> + uint64_t idle, prev, ts[2];
> + unsigned long slept, cycles;
> + unsigned long *done;
> + int fd;
> +
> + fd = open_pmu(i915, I915_PMU_RC6_RESIDENCY);
> + igt_require(__pmu_wait_for_rc6(fd));
> +
> + /* While idle check full RC6. */
> + prev = __pmu_read_single(fd, &ts[0]);
> + slept = measured_usleep(duration_ns / 1000);
> + idle = __pmu_read_single(fd, &ts[1]);
> + igt_debug("slept=%lu perf=%"PRIu64"\n", slept, ts[1] - ts[0]);
> + assert_within_epsilon(idle - prev, ts[1] - ts[0], 5);
> +
> + /* Setup up a very light load */
> + done = mmap(0, 4096, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
> + igt_fork(child, 1) {
> + struct drm_i915_gem_exec_object2 obj = {
> + .handle = batch_create(i915),
> + };
> + struct drm_i915_gem_execbuffer2 execbuf = {
> + .buffers_ptr = to_user_pointer(&obj),
> + .buffer_count = 1,
> + };
> +
> + do {
> + struct timespec tv = {};
> +
> + igt_seconds_elapsed(&tv);
> +
> + gem_execbuf(i915, &execbuf);
> + gem_sync(i915, obj.handle);
> + done[1]++;
> +
> + usleep(igt_seconds_elapsed(&tv) / 10); /* => 1% busy */
igt_nsec_elapsed()?
Not too familiar with the perf interface but I assume event[0] read is
the RC6 residency, while event[1] is the duration while the event was
enabled (so the duration since the event file was opened?). Looks ok:
Reviewed-by: Imre Deak <imre.deak at intel.com>
> + } while (!*done);
> + }
> +
> + /* While very nearly idle (idle to within tolerance), except full RC6 */
> + cycles = -done[1];
> + prev = __pmu_read_single(fd, &ts[0]);
> + slept = measured_usleep(duration_ns / 1000);
> + idle = __pmu_read_single(fd, &ts[1]);
> + cycles += done[1];
> + igt_debug("slept=%lu perf=%"PRIu64", cycles=%lu\n",
> + slept, ts[1] - ts[0], cycles);
> + igt_assert(cycles > 0);
> + assert_within_epsilon(idle - prev, ts[1] - ts[0], 5);
> +
> + close(fd);
> +
> + *done = 1;
> + igt_waitchildren();
> +}
> +
> igt_main
> {
> unsigned int rc6_enabled = 0;
> unsigned int devid = 0;
> + int i915 = -1;
>
> /* Use drm_open_driver to verify device existence */
> igt_fixture {
> - int fd;
> -
> - fd = drm_open_driver(DRIVER_INTEL);
> - devid = intel_get_drm_devid(fd);
> - sysfs = igt_sysfs_open(fd);
> + i915 = drm_open_driver(DRIVER_INTEL);
> + devid = intel_get_drm_devid(i915);
> + sysfs = igt_sysfs_open(i915);
>
> igt_require(has_rc6_residency("rc6"));
>
> /* Make sure rc6 counters are running */
> - igt_drop_caches_set(fd, DROP_IDLE);
> + igt_drop_caches_set(i915, DROP_IDLE);
> igt_require(wait_for_rc6());
>
> - close(fd);
> -
> rc6_enabled = get_rc6_enabled_mask();
> igt_require(rc6_enabled & RC6_ENABLED);
> }
>
> + igt_subtest("rc6-perf") {
> + igt_require_gem(i915);
> + gem_quiescent_gpu(i915);
> +
> + rc6_perf(i915);
> + }
> +
> igt_subtest("rc6-accuracy") {
> struct residencies res;
>
> @@ -235,4 +385,8 @@ igt_main
> measure_residencies(devid, rc6_enabled, &res);
> residency_accuracy(res.media_rc6, res.duration, "media_rc6");
> }
> +
> + igt_fixture
> + close(i915);
> +
> }
> diff --git a/tests/meson.build b/tests/meson.build
> index 570de5459..a79d22ba1 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -232,7 +232,6 @@ i915_progs = [
> 'i915_module_load',
> 'i915_pm_backlight',
> 'i915_pm_lpsp',
> - 'i915_pm_rc6_residency',
> 'i915_pm_rpm',
> 'i915_pm_dc',
> 'i915_pm_rps',
> @@ -336,6 +335,14 @@ test_executables += executable('gem_mmap_offset',
> install : true)
> test_list += 'gem_mmap_offset'
>
> +test_executables += executable('i915_pm_rc6_residency',
> + join_paths('i915', 'i915_pm_rc6_residency.c'),
> + dependencies : test_deps + [ lib_igt_perf ],
> + install_dir : libexecdir,
> + install_rpath : libexecdir_rpathdir,
> + install : true)
> +test_list += 'i915_pm_rc6_residency'
> +
> test_executables += executable('perf_pmu', 'perf_pmu.c',
> dependencies : test_deps + [ lib_igt_perf ],
> install_dir : libexecdir,
> --
> 2.25.0.rc2
>
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