Re: [igt-dev] [PATCH i-g-t] igt: Add gem_ctx_freq to exercise requesting freq via sysfs

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> Once propposed long ago was per-context frequency controls. As part of
> that this test suite was written, which among its tests covered the
> interaction of sysfs with the per-context controls. While we wait again
> for approval of the per-context API, we can at least leverage the sysfs
> tests to provide sorely lacking coverage of the sysfs knobs.

s/propposed/proposed.
s/its/it's

>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

> ---
>  tests/Makefile.am         |   1 +
>  tests/Makefile.sources    |   3 +
>  tests/i915/gem_ctx_freq.c | 216 ++++++++++++++++++++++++++++++++++++++
>  tests/meson.build         |   8 ++
>  4 files changed, 228 insertions(+)
>  create mode 100644 tests/i915/gem_ctx_freq.c
>
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 7d71df8c7..7fe60b78e 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -93,6 +93,7 @@ gem_create_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
>  gem_create_LDADD = $(LDADD) -lpthread -latomic
>  gem_close_race_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
>  gem_close_race_LDADD = $(LDADD) -lpthread
> +gem_ctx_freq_LDADD = $(LDADD) $(top_builddir)/lib/libigt_perf.la
>  gem_ctx_thrash_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
>  gem_ctx_thrash_LDADD = $(LDADD) -lpthread
>  gem_ctx_sseu_LDADD = $(LDADD) $(top_builddir)/lib/libigt_perf.la
> diff --git a/tests/Makefile.sources b/tests/Makefile.sources
> index f2dcca6d7..d86f9c263 100644
> --- a/tests/Makefile.sources
> +++ b/tests/Makefile.sources
> @@ -152,6 +152,9 @@ gem_ctx_engines_SOURCES = i915/gem_ctx_engines.c
>  TESTS_progs += gem_ctx_exec
>  gem_ctx_exec_SOURCES = i915/gem_ctx_exec.c
>  
> +TESTS_progs += gem_ctx_freq
> +gem_ctx_freq_SOURCES = i915/gem_ctx_freq.c
> +
>  TESTS_progs += gem_ctx_isolation
>  gem_ctx_isolation_SOURCES = i915/gem_ctx_isolation.c
>  
> diff --git a/tests/i915/gem_ctx_freq.c b/tests/i915/gem_ctx_freq.c
> new file mode 100644
> index 000000000..bc093654a
> --- /dev/null
> +++ b/tests/i915/gem_ctx_freq.c
> @@ -0,0 +1,216 @@
> +/*
> + * Copyright © 2018 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <sched.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <unistd.h>
> +
> +#include "igt.h"
> +#include "igt_perf.h"
> +#include "igt_sysfs.h"
> +#include "sw_sync.h"
> +
> +#define SAMPLE_PERIOD (USEC_PER_SEC / 10)
> +#define PMU_TOLERANCE 100
> +
> +static int sysfs = -1;
> +
> +static void kick_rps_worker(void)
> +{
> +	sched_yield();
> +	usleep(SAMPLE_PERIOD);
> +}
> +
> +static double measure_frequency(int pmu, int period_us)
> +{
> +	uint64_t data[2];
> +	uint64_t d_t, d_v;
> +
> +	kick_rps_worker(); /* let the kthreads (intel_rps_work) run */
> +
> +	igt_assert_eq(read(pmu, data, sizeof(data)), sizeof(data));
> +	d_v = -data[0];
> +	d_t = -data[1];
> +
> +	usleep(period_us);
> +
> +	igt_assert_eq(read(pmu, data, sizeof(data)), sizeof(data));
> +	d_v += data[0];
> +	d_t += data[1];
> +
> +	return d_v * 1e9 / d_t;
> +}
> +
> +static bool __pmu_within_tolerance(double actual, double target)
> +{
> +	return (actual > target - PMU_TOLERANCE &&
> +		actual < target + PMU_TOLERANCE);
> +}
> +
> +static void pmu_assert(double actual, double target)
> +{
> +	igt_assert_f(__pmu_within_tolerance(actual, target),
> +		     "Measured frequency %.2fMHz, is beyond target %.0f±%dMhz\n",
> +		     actual, target, PMU_TOLERANCE);
> +}
> +
> +static void busy_wait_until_idle(int i915, igt_spin_t *spin)
> +{
> +	igt_spin_end(spin);
> +	do {
> +		usleep(10000);
> +	} while (gem_bo_busy(i915, spin->handle));
> +}
> +
> +static void __igt_spin_free_idle(int i915, igt_spin_t *spin)
> +{
> +	busy_wait_until_idle(i915, spin);
> +
> +	igt_spin_free(i915, spin);
> +}
> +
> +#define TRIANGLE_SIZE(x) (2 * (x) + 1)
> +static void triangle_fill(uint32_t *t, unsigned int nstep,
> +			  uint32_t min, uint32_t max)
> +{
> +	for (unsigned int step = 0; step <= 2*nstep; step++) {
> +		int frac = step > nstep ? 2*nstep - step : step;
> +		t[step] = min + (max - min) * frac / nstep;
> +	}
> +}
> +
> +static void set_sysfs_freq(uint32_t min, uint32_t max)
> +{
> +	igt_sysfs_printf(sysfs, "gt_min_freq_mhz", "%u", min);
> +	igt_sysfs_printf(sysfs, "gt_max_freq_mhz", "%u", max);
> +}
> +
> +static void get_sysfs_freq(uint32_t *min, uint32_t *max)
> +{
> +	igt_sysfs_scanf(sysfs, "gt_min_freq_mhz", "%u", min);
> +	igt_sysfs_scanf(sysfs, "gt_max_freq_mhz", "%u", max);
> +}
> +
> +static void sysfs_range(int i915)
> +{
> +#define N_STEPS 10
> +	uint32_t frequencies[TRIANGLE_SIZE(N_STEPS)];
> +	uint32_t sys_min, sys_max;
> +	igt_spin_t *spin;
> +	double measured;
> +	int pmu;
> +
> +	/*
> +	 * The sysfs interface sets the global limits and overrides the
> +	 * user's request. So we can to check that if the user requests
> +	 * a range outside of the sysfs, the requests are only run at the
> +	 * constriained sysfs range.
> +	 */
> +
> +	get_sysfs_freq(&sys_min, &sys_max);
> +	igt_info("System min freq: %dMHz; max freq: %dMHz\n", sys_min, sys_max);
> +
> +	triangle_fill(frequencies, N_STEPS, sys_min, sys_max);
> +
> +	pmu = perf_i915_open(I915_PMU_REQUESTED_FREQUENCY);
> +	igt_require(pmu >= 0);
> +
> +	for (int outer = 0; outer <= 2*N_STEPS; outer++) {
> +		uint32_t sys_freq = frequencies[outer];
> +		uint32_t cur, discard;
> +
> +		gem_quiescent_gpu(i915);
> +		spin = igt_spin_new(i915);
> +		usleep(10000);
> +
> +		set_sysfs_freq(sys_freq, sys_freq);
> +		get_sysfs_freq(&cur, &discard);
> +
> +		measured = measure_frequency(pmu, SAMPLE_PERIOD);
> +		igt_debugfs_dump(i915, "i915_rps_boost_info");
> +
> +		set_sysfs_freq(sys_min, sys_max);
> +		__igt_spin_free_idle(i915, spin);
> +
> +		igt_info("sysfs: Measured %.1fMHz, expected %dMhz\n",
> +			 measured, cur);
> +		pmu_assert(measured, cur);
> +	}
> +	gem_quiescent_gpu(i915);
> +
> +	close(pmu);
> +
> +#undef N_STEPS
> +}
> +
> +static void restore_sysfs_freq(int sig)
> +{
> +	char buf[256];
> +
> +	if (igt_sysfs_read(sysfs, "gt_RPn_freq_mhz", buf, sizeof(buf)) > 0) {
> +		igt_sysfs_set(sysfs, "gt_idle_freq_mhz", buf);
> +		igt_sysfs_set(sysfs, "gt_min_freq_mhz", buf);
> +	}
> +
> +	if (igt_sysfs_read(sysfs, "gt_RP0_freq_mhz", buf, sizeof(buf)) > 0) {
> +		igt_sysfs_set(sysfs, "gt_max_freq_mhz", buf);
> +		igt_sysfs_set(sysfs, "gt_boost_freq_mhz", buf);
> +	}
> +}
> +
> +static void disable_boost(int i915)
> +{
> +	char *value;
> +
> +	value = igt_sysfs_get(i915, "gt_RPn_freq_mhz");
> +	igt_sysfs_set(i915, "gt_min_freq_mhz", value);
> +	igt_sysfs_set(i915, "gt_boost_freq_mhz", value);
> +	free(value);
> +
> +	value = igt_sysfs_get(i915, "gt_RP0_freq_mhz");
> +	igt_sysfs_set(i915, "gt_max_freq_mhz", value);
> +	free(value);
> +}
> +
> +igt_main
> +{
> +	int i915 = -1;
> +
> +	igt_fixture {
> +		i915 = drm_open_driver(DRIVER_INTEL);
> +		igt_require_gem(i915);
> +
> +		sysfs = igt_sysfs_open(i915);
> +		igt_assert(sysfs != -1);
> +		igt_install_exit_handler(restore_sysfs_freq);
> +
> +		disable_boost(sysfs);
> +	}
> +
> +	igt_subtest_f("sysfs")
> +		sysfs_range(i915);
> +}
> diff --git a/tests/meson.build b/tests/meson.build
> index ca2b8b62d..a909d271e 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -291,6 +291,14 @@ test_executables += executable('gem_create',
>  	   install : true)
>  test_list += 'gem_create'
>  
> +test_executables += executable('gem_ctx_freq',
> +	   join_paths('i915', 'gem_ctx_freq.c'),
> +	   dependencies : test_deps + [ lib_igt_perf ],
> +	   install_dir : libexecdir,
> +	   install_rpath : libexecdir_rpathdir,
> +	   install : true)
> +test_list += 'gem_ctx_freq'
> +
>  test_executables += executable('gem_ctx_sseu',
>  	   join_paths('i915', 'gem_ctx_sseu.c'),
>  	   dependencies : test_deps + [ lib_igt_perf ],
> -- 
> 2.24.0
>
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