igt: Add gem_ctx_freq to exercise requesting freq via sysfs

Once proposed 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.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

1 files changed, 216 insertions, 0 deletions

diff --git a/tests/i915/gem_ctx_freq.c b/tests/i915/gem_ctx_freq.c
new file mode 100644
index 00000000..bc093654
--- /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);
+}