From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: References: <20201214204430.677828-1-chris@chris-wilson.co.uk> <4cd49f52-efe8-9367-c56b-d1f5382a4580@linux.intel.com> <160802562689.8745.13825208972464849155@build.alporthouse.com> From: Tvrtko Ursulin Message-ID: <0d5bee82-0764-54b6-1623-8303375921b9@linux.intel.com> Date: Tue, 15 Dec 2020 09:51:08 +0000 MIME-Version: 1.0 In-Reply-To: <160802562689.8745.13825208972464849155@build.alporthouse.com> Content-Language: en-US Subject: Re: [Intel-gfx] [igt-dev] [PATCH i-g-t] i915/gem_exec_schedule: Measure timeslice distribution when oversaturated List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Chris Wilson , intel-gfx@lists.freedesktop.org Cc: igt-dev@lists.freedesktop.org List-ID: On 15/12/2020 09:47, Chris Wilson wrote: > Quoting Tvrtko Ursulin (2020-12-15 09:41:09) >> >> On 14/12/2020 20:44, Chris Wilson wrote: >>> Check that timeslices for an oversaturated system (where there is more >>> work than can be supported by a single engine) are evenly distributed >>> between the clients. >>> >>> Signed-off-by: Chris Wilson >>> Cc: Tvrtko Ursulin >>> --- >>> tests/i915/gem_exec_schedule.c | 179 +++++++++++++++++++++++++++++++++ >>> 1 file changed, 179 insertions(+) >>> >>> diff --git a/tests/i915/gem_exec_schedule.c b/tests/i915/gem_exec_schedule.c >>> index f23d63ac3..263f1dd78 100644 >>> --- a/tests/i915/gem_exec_schedule.c >>> +++ b/tests/i915/gem_exec_schedule.c >>> @@ -2516,6 +2516,154 @@ static void measure_semaphore_power(int i915) >>> rapl_close(&pkg); >>> } >>> >>> +static int read_timestamp_frequency(int i915) >>> +{ >>> + int value = 0; >>> + drm_i915_getparam_t gp = { >>> + .value = &value, >>> + .param = I915_PARAM_CS_TIMESTAMP_FREQUENCY, >>> + }; >>> + ioctl(i915, DRM_IOCTL_I915_GETPARAM, &gp); >>> + return value; >>> +} >>> + >>> +static uint64_t div64_u64_round_up(uint64_t x, uint64_t y) >>> +{ >>> + return (x + y - 1) / y; >>> +} >>> + >>> +static uint64_t ticks_to_ns(int i915, uint64_t ticks) >>> +{ >>> + return div64_u64_round_up(ticks * NSEC_PER_SEC, >>> + read_timestamp_frequency(i915)); >>> +} >>> + >>> +static int cmp_u32(const void *A, const void *B) >>> +{ >>> + const uint32_t *a = A, *b = B; >>> + >>> + if (*a < *b) >>> + return -1; >>> + else if (*a > *b) >>> + return 1; >>> + else >>> + return 0; >>> +} >>> + >>> +static uint32_t read_ctx_timestamp(int i915, >>> + uint32_t ctx, >>> + const struct intel_execution_engine2 *e) >>> +{ >>> + const int use_64b = intel_gen(intel_get_drm_devid(i915)) >= 8; >>> + const uint32_t base = gem_engine_mmio_base(i915, e->name); >>> + struct drm_i915_gem_relocation_entry reloc; >>> + struct drm_i915_gem_exec_object2 obj = { >>> + .handle = gem_create(i915, 4096), >>> + .offset = 32 << 20, >>> + .relocs_ptr = to_user_pointer(&reloc), >>> + .relocation_count = 1, >>> + }; >>> + struct drm_i915_gem_execbuffer2 execbuf = { >>> + .buffers_ptr = to_user_pointer(&obj), >>> + .buffer_count = 1, >>> + .flags = e->flags, >>> + .rsvd1 = ctx, >>> + }; >>> +#define RUNTIME (base + 0x3a8) >>> + uint32_t *map, *cs; >>> + uint32_t ts; >>> + >>> + igt_require(base); >>> + >>> + cs = map = gem_mmap__device_coherent(i915, obj.handle, >>> + 0, 4096, PROT_WRITE); >>> + >>> + *cs++ = 0x24 << 23 | (1 + use_64b); /* SRM */ >>> + *cs++ = RUNTIME; >>> + memset(&reloc, 0, sizeof(reloc)); >>> + reloc.target_handle = obj.handle; >>> + reloc.presumed_offset = obj.offset; >>> + reloc.offset = offset_in_page(cs); >>> + reloc.delta = 4000; >>> + *cs++ = obj.offset + 4000; >>> + *cs++ = obj.offset >> 32; >>> + >>> + *cs++ = MI_BATCH_BUFFER_END; >>> + >>> + gem_execbuf(i915, &execbuf); >>> + gem_sync(i915, obj.handle); >>> + gem_close(i915, obj.handle); >>> + >>> + ts = map[1000]; >>> + munmap(map, 4096); >>> + >>> + return ts; >>> +} >>> + >>> +static void fairslice(int i915, >>> + const struct intel_execution_engine2 *e, >>> + unsigned long flags, >>> + int duration) >>> +{ >>> + const double timeslice_duration_ns = 1e6; >>> + igt_spin_t *spin = NULL; >>> + double threshold; >>> + uint32_t ctx[3]; >>> + uint32_t ts[3]; >>> + >>> + for (int i = 0; i < ARRAY_SIZE(ctx); i++) { >>> + ctx[i] = gem_context_clone_with_engines(i915, 0); >>> + if (spin == NULL) { >>> + spin = __igt_spin_new(i915, >>> + .ctx = ctx[i], >>> + .engine = e->flags, >>> + .flags = flags); >>> + } else { >>> + struct drm_i915_gem_execbuffer2 eb = { >>> + .buffer_count = 1, >>> + .buffers_ptr = to_user_pointer(&spin->obj[IGT_SPIN_BATCH]), >>> + .flags = e->flags, >>> + .rsvd1 = ctx[i], >>> + }; >>> + gem_execbuf(i915, &eb); >>> + } >>> + } >>> + >>> + sleep(duration); /* over the course of many timeslices */ >>> + >>> + igt_assert(gem_bo_busy(i915, spin->handle)); >>> + igt_spin_end(spin); >>> + for (int i = 0; i < ARRAY_SIZE(ctx); i++) >>> + ts[i] = read_ctx_timestamp(i915, ctx[i], e); >>> + >>> + for (int i = 0; i < ARRAY_SIZE(ctx); i++) >>> + gem_context_destroy(i915, ctx[i]); >>> + igt_spin_free(i915, spin); >>> + >>> + /* >>> + * If we imagine that the timeslices are randomly distributed to >>> + * the virtual engines, we would expect the variation to be modelled >>> + * by a drunken walk; ergo sqrt(num_timeslices). >>> + */ >>> + threshold = sqrt(1e9 * duration / timeslice_duration_ns); >>> + threshold *= timeslice_duration_ns; >>> + threshold *= 2; /* CI safety factor before crying wolf */ >>> + >>> + qsort(ts, 3, sizeof(*ts), cmp_u32); >>> + igt_info("%s: [%.1f, %.1f, %.1f] ms, expect %1.f +- %.1fms\n", e->name, >>> + 1e-6 * ticks_to_ns(i915, ts[0]), >>> + 1e-6 * ticks_to_ns(i915, ts[1]), >>> + 1e-6 * ticks_to_ns(i915, ts[2]), >>> + 1e3 * duration / 3, >>> + 1e-6 * threshold); >>> + >>> + igt_assert_f(ts[2], "CTX_TIMESTAMP not reported!\n"); >>> + igt_assert_f(ticks_to_ns(i915, ts[2] - ts[0]) < 2 * threshold, >> >> Is this second threshold x2 by accident? > > The drunken walk model's variance is evenly distributed about the mean > (one-sided). We are comparing max-min, so a two-sided range test. Ah okay. Reviewed-by: Tvrtko Ursulin Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx