[igt-dev] [PATCH i-g-t 2/2] tests/perf: new tests for parameterized OA buffer polling
Lionel Landwerlin
lionel.g.landwerlin at intel.com
Fri Mar 13 11:43:35 UTC 2020
On 13/03/2020 01:05, Umesh Nerlige Ramappa wrote:
> From: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>
> 2 new tests verifying that the OA buffer is properly checked at the
> frequency specified by userspace.
>
> v2: (Umesh)
> - Capture start_times in test_polling
> - Second parameterized test used a 500us hrtimer. Occassionally, this
> timing does not fall within the duration/100 requirement for the time
> spent in kernel. Change this value to 2ms to accommodate all
> platforms.
>
> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> ---
> tests/perf.c | 132 ++++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 98 insertions(+), 34 deletions(-)
>
> diff --git a/tests/perf.c b/tests/perf.c
> index 5e818030..f1831550 100644
> --- a/tests/perf.c
> +++ b/tests/perf.c
> @@ -234,6 +234,24 @@ get_oa_format(enum drm_i915_oa_format format)
> return gen8_oa_formats[format];
> }
>
> +static char *
> +pretty_print_oa_period(uint64_t oa_period_ns)
> +{
> + static char result[100];
> + static const char *units[4] = { "ns", "us", "ms", "s" };
> + double val = oa_period_ns;
> + int iter = 0;
> +
> + while (iter < (ARRAY_SIZE(units) - 1) &&
> + val >= 1000.0f) {
> + val /= 1000.0f;
> + iter++;
> + }
> +
> + snprintf(result, sizeof(result), "%.3f%s", val, units[iter]);
> + return result;
> +}
> +
> static void
> __perf_close(int fd)
> {
> @@ -1921,15 +1939,9 @@ get_time(void)
> * kernelspace.
> */
> static void
> -test_blocking(void)
> +test_blocking(uint64_t requested_oa_period, bool set_kernel_hrtimer, uint64_t kernel_hrtimer)
> {
> - /* ~40 milliseconds
> - *
> - * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
> - * scheduling (liable to kick in when we make blocking poll()s/reads)
> - * from interfering with the test.
> - */
> - int oa_exponent = max_oa_exponent_for_period_lte(40000000);
> + int oa_exponent = max_oa_exponent_for_period_lte(requested_oa_period);
> uint64_t oa_period = oa_exponent_to_ns(oa_exponent);
> uint64_t properties[] = {
> /* Include OA reports in samples */
> @@ -1939,11 +1951,16 @@ test_blocking(void)
> DRM_I915_PERF_PROP_OA_METRICS_SET, test_set->perf_oa_metrics_set,
> DRM_I915_PERF_PROP_OA_FORMAT, test_set->perf_oa_format,
> DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +
> + /* Kernel configuration (optional) */
> + DRM_I915_PERF_PROP_POLL_OA_DELAY, kernel_hrtimer,
> };
> struct drm_i915_perf_open_param param = {
> .flags = I915_PERF_FLAG_FD_CLOEXEC |
> I915_PERF_FLAG_DISABLED,
> - .num_properties = sizeof(properties) / 16,
> + .num_properties = (set_kernel_hrtimer ?
> + (ARRAY_SIZE(properties) / 2) :
> + ((ARRAY_SIZE(properties) / 2) - 1)),
There is a NUM_PROPERTIES() macro at the top of the file you could reuse
for this :
set_kernel_hrtimer ? NUM_PROPERTIES(properties) :
(NUM_PROPERTIES(properties) - 1)
> .properties_ptr = to_user_pointer(properties),
> };
> uint8_t buf[1024 * 1024];
> @@ -1965,7 +1982,7 @@ test_blocking(void)
> * the knowledge that that the driver uses a 200Hz hrtimer (5ms period)
> * to check for data and giving some time to read().
> */
> - int min_iterations = (test_duration_ns / (oa_period + 6000000ull));
> + int min_iterations = (test_duration_ns / (oa_period + kernel_hrtimer + kernel_hrtimer / 5));
>
> int64_t start, end;
> int n = 0;
> @@ -1975,9 +1992,10 @@ test_blocking(void)
> times(&start_times);
>
> igt_debug("tick length = %dns, test duration = %"PRIu64"ns, min iter. = %d,"
> - " estimated max iter. = %d, oa_period = %"PRIu64"ns\n",
> + " estimated max iter. = %d, oa_period = %s\n",
> (int)tick_ns, test_duration_ns,
> - min_iterations, max_iterations, oa_period);
> + min_iterations, max_iterations,
> + pretty_print_oa_period(oa_period));
>
> /* In the loop we perform blocking polls while the HW is sampling at
> * ~25Hz, with the expectation that we spend most of our time blocked
> @@ -2079,15 +2097,9 @@ test_blocking(void)
> }
>
> static void
> -test_polling(void)
> +test_polling(uint64_t requested_oa_period, bool set_kernel_hrtimer, uint64_t kernel_hrtimer)
> {
> - /* ~40 milliseconds
> - *
> - * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
> - * scheduling (liable to kick in when we make blocking poll()s/reads)
> - * from interfering with the test.
> - */
> - int oa_exponent = max_oa_exponent_for_period_lte(40000000);
> + int oa_exponent = max_oa_exponent_for_period_lte(requested_oa_period);
> uint64_t oa_period = oa_exponent_to_ns(oa_exponent);
> uint64_t properties[] = {
> /* Include OA reports in samples */
> @@ -2097,12 +2109,17 @@ test_polling(void)
> DRM_I915_PERF_PROP_OA_METRICS_SET, test_set->perf_oa_metrics_set,
> DRM_I915_PERF_PROP_OA_FORMAT, test_set->perf_oa_format,
> DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +
> + /* Kernel configuration (optional) */
> + DRM_I915_PERF_PROP_POLL_OA_DELAY, kernel_hrtimer,
> };
> struct drm_i915_perf_open_param param = {
> .flags = I915_PERF_FLAG_FD_CLOEXEC |
> I915_PERF_FLAG_DISABLED |
> I915_PERF_FLAG_FD_NONBLOCK,
> - .num_properties = sizeof(properties) / 16,
> + .num_properties = (set_kernel_hrtimer ?
> + (ARRAY_SIZE(properties) / 2) :
> + ((ARRAY_SIZE(properties) / 2) - 1)),
Same here.
> .properties_ptr = to_user_pointer(properties),
> };
> uint8_t buf[1024 * 1024];
> @@ -2116,15 +2133,16 @@ test_polling(void)
> int n_extra_iterations = 0;
>
> /* It's a bit tricky to put a lower limit here, but we expect a
> - * relatively low latency for seeing reports, while we don't currently
> - * give any control over this in the api.
> + * relatively low latency for seeing reports.
> *
> - * We assume a maximum latency of 6 millisecond to deliver a POLLIN and
> - * read() after a new sample is written (46ms per iteration) considering
> - * the knowledge that that the driver uses a 200Hz hrtimer (5ms period)
> - * to check for data and giving some time to read().
> + * We assume a maximum latency of kernel_hrtimer + some margin
> + * to deliver a POLLIN and read() after a new sample is
> + * written (40ms + hrtimer + margin per iteration) considering
> + * the knowledge that that the driver uses a 200Hz hrtimer
> + * (5ms period) to check for data and giving some time to
> + * read().
> */
> - int min_iterations = (test_duration_ns / (oa_period + 6000000ull));
> + int min_iterations = (test_duration_ns / (oa_period + (kernel_hrtimer + kernel_hrtimer / 5)));
> int64_t start, end;
> int n = 0;
>
> @@ -2132,8 +2150,9 @@ test_polling(void)
>
> times(&start_times);
>
> - igt_debug("tick length = %dns, test duration = %"PRIu64"ns, min iter. = %d, max iter. = %d\n",
> - (int)tick_ns, test_duration_ns,
> + igt_debug("tick length = %dns, oa period = %s, "
> + "test duration = %"PRIu64"ns, min iter. = %d, max iter. = %d\n",
> + (int)tick_ns, pretty_print_oa_period(oa_period), test_duration_ns,
> min_iterations, max_iterations);
>
> /* In the loop we perform blocking polls while the HW is sampling at
> @@ -4502,6 +4521,23 @@ test_sysctl_defaults(void)
> igt_assert_eq(max_freq, 100000);
> }
>
> +static int i915_perf_revision(int fd)
> +{
> + drm_i915_getparam_t gp;
> + int value = 1, ret;
> +
> + gp.param = I915_PARAM_PERF_REVISION;
> + gp.value = &value;
> + ret = igt_ioctl(drm_fd, DRM_IOCTL_I915_GETPARAM, &gp);
> + if (ret == -1) {
> + /* If the param is missing, consider version 1. */
> + igt_assert_eq(errno, EINVAL);
> + return 1;
> + }
> +
> + return value;
> +}
> +
> igt_main
> {
> igt_fixture {
> @@ -4584,11 +4620,39 @@ igt_main
> igt_subtest("enable-disable")
> test_enable_disable();
>
> - igt_subtest("blocking")
> - test_blocking();
> + igt_subtest("blocking") {
> + test_blocking(40 * 1000 * 1000 /* 40ms oa period */,
> + false /* set_kernel_hrtimer */,
> + 5 * 1000 * 1000 /* default 5ms/200Hz hrtimer */);
> + }
> +
> + igt_subtest("blocking-parameterized") {
> + igt_require(i915_perf_revision(drm_fd) >= 2);
The kernel patches are revision 4.
> +
> + test_blocking(10 * 1000 * 1000 /* 10ms oa period */,
> + true /* set_kernel_hrtimer */,
> + 40 * 1000 * 1000 /* default 40ms hrtimer */);
> + test_blocking(500 * 1000 /* 500us oa period */,
> + true /* set_kernel_hrtimer */,
> + 2 * 1000 * 1000 /* default 2ms hrtimer */);
> + }
>
> - igt_subtest("polling")
> - test_polling();
> + igt_subtest("polling") {
> + test_polling(40 * 1000 * 1000 /* 40ms oa period */,
> + false /* set_kernel_hrtimer */,
> + 5 * 1000 * 1000 /* default 5ms/200Hz hrtimer */);
> + }
> +
> + igt_subtest("polling-parameterized") {
> + igt_require(i915_perf_revision(drm_fd) >= 2);
Same revision 4 here.
> +
> + test_polling(10 * 1000 * 1000 /* 10ms oa period */,
> + true /* set_kernel_hrtimer */,
> + 40 * 1000 * 1000 /* default 40ms hrtimer */);
> + test_polling(500 * 1000 /* 500us oa period */,
> + true /* set_kernel_hrtimer */,
> + 2 * 1000 * 1000 /* default 2ms hrtimer */);
> + }
>
> igt_subtest("short-reads")
> test_short_reads();
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