From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: References: <20201214105123.542518-1-chris@chris-wilson.co.uk> <20201214105123.542518-2-chris@chris-wilson.co.uk> From: Tvrtko Ursulin Message-ID: <8a85eb50-1591-583d-30ae-18264774ae2a@linux.intel.com> Date: Mon, 14 Dec 2020 15:51:24 +0000 MIME-Version: 1.0 In-Reply-To: <20201214105123.542518-2-chris@chris-wilson.co.uk> Content-Language: en-US Subject: Re: [igt-dev] [PATCH i-g-t 2/4] i915/gem_exec_balancer: Measure timeslicing fairness 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: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" To: Chris Wilson , intel-gfx@lists.freedesktop.org Cc: igt-dev@lists.freedesktop.org List-ID: On 14/12/2020 10:51, Chris Wilson wrote: > Oversaturate the virtual engines on the system and check that each > workload receives a fair share of the available GPU time. A simpler one to start with, I support that. > > Signed-off-by: Chris Wilson > --- > tests/i915/gem_exec_balancer.c | 154 +++++++++++++++++++++++++++++++++ > 1 file changed, 154 insertions(+) > > diff --git a/tests/i915/gem_exec_balancer.c b/tests/i915/gem_exec_balancer.c > index 35a032ccb..5efd586ad 100644 > --- a/tests/i915/gem_exec_balancer.c > +++ b/tests/i915/gem_exec_balancer.c > @@ -2763,6 +2763,157 @@ static void smoketest(int i915, int timeout) > gem_close(i915, batch[0].handle); > } > > +static uint32_t read_ctx_timestamp(int i915, uint32_t ctx) > +{ > + 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, > + .rsvd1 = ctx, > + }; > + uint32_t *map, *cs; > + uint32_t ts; > + > + cs = map = gem_mmap__device_coherent(i915, obj.handle, > + 0, 4096, PROT_WRITE); > + > + *cs++ = 0x24 << 23 | 1 << 19 | 2; /* relative SRM */ > + *cs++ = 0x3a8; /* CTX_TIMESTAMP */ > + 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 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 int read_ctx_timestamp_frequency(int i915) > +{ > + int value = 12500000; /* icl!!! are you feeling alright? CTX vs CS */ > + drm_i915_getparam_t gp = { > + .value = &value, > + .param = I915_PARAM_CS_TIMESTAMP_FREQUENCY, > + }; > + if (intel_gen(intel_get_drm_devid(i915)) != 11) > + 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_ctx_timestamp_frequency(i915)); > +} > + > +static void __fairslice(int i915, > + const struct i915_engine_class_instance *ci, > + unsigned int count) > +{ > + igt_spin_t *spin = NULL; > + uint32_t ctx[count + 1]; > + uint32_t ts[count + 1]; > + > + igt_debug("Launching %zd spinners on %s\n", > + ARRAY_SIZE(ctx), class_to_str(ci->engine_class)); > + igt_assert(ARRAY_SIZE(ctx) >= 3); > + > + for (int i = 0; i < ARRAY_SIZE(ctx); i++) { > + ctx[i] = load_balancer_create(i915, ci, count); > + if (spin == NULL) { > + spin = __igt_spin_new(i915, .ctx = ctx[i]); > + } else { > + struct drm_i915_gem_execbuffer2 eb = { > + .buffer_count = 1, > + .buffers_ptr = to_user_pointer(&spin->obj[IGT_SPIN_BATCH]), > + .rsvd1 = ctx[i], > + }; > + gem_execbuf(i915, &eb); > + } > + } > + > + sleep(2); /* over the course of many timeslices */ > + > + igt_assert(gem_bo_busy(i915, spin->handle)); > + igt_spin_end(spin); > + igt_debug("Cancelled spinners\n"); > + > + for (int i = 0; i < ARRAY_SIZE(ctx); i++) > + ts[i] = read_ctx_timestamp(i915, ctx[i]); Now if we had context stats ioctl. :) > + > + for (int i = 0; i < ARRAY_SIZE(ctx); i++) > + gem_context_destroy(i915, ctx[i]); > + igt_spin_free(i915, spin); > + > + qsort(ts, ARRAY_SIZE(ctx), sizeof(*ts), cmp_u32); > + igt_info("%s: [%.1f, %.1f, %.1f] ms, expect %1.fms\n", > + class_to_str(ci->engine_class), > + 1e-6 * ticks_to_ns(i915, ts[0]), > + 1e-6 * ticks_to_ns(i915, ts[(count + 1) / 2]), > + 1e-6 * ticks_to_ns(i915, ts[count]), > + 2e3 * count / ARRAY_SIZE(ctx)); > + > + igt_assert_f(ts[count], "CTX_TIMESTAMP not reported!\n"); > + igt_assert_f((ts[count] - ts[0]) * 6 < ts[(count + 1) / 2], > + "Range of timeslices greater than tolerable: %.2fms > %.2fms; unfair!\n", > + 1e-6 * ticks_to_ns(i915, ts[count] - ts[0]), > + 1e-6 * ticks_to_ns(i915, ts[(count + 1) / 2]) / 6); Just put a comment saying what is the criteria please. Six ranges vs median, must be some statistical thing but that's not my forte. > +} > + > +static void fairslice(int i915) > +{ > + /* Relative CS mmio */ > + igt_require(intel_gen(intel_get_drm_devid(i915)) >= 11); > + > + for (int class = 0; class < 32; class++) { > + struct i915_engine_class_instance *ci; > + unsigned int count = 0; > + > + ci = list_engines(i915, 1u << class, &count); > + if (!ci || count < 2) { > + free(ci); > + continue; > + } > + > + __fairslice(i915, ci, count); > + free(ci); > + } > +} > + > static bool has_context_engines(int i915) > { > struct drm_i915_gem_context_param p = { > @@ -2848,6 +2999,9 @@ igt_main > full(i915, p->flags); > } > > + igt_subtest("fairslice") > + fairslice(i915); > + > igt_subtest("nop") > nop(i915); > > Otherwise LGTM. Reviewed-by: Tvrtko Ursulin Regards, Tvrtko _______________________________________________ igt-dev mailing list igt-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/igt-dev