[igt-dev] [PATCH i-g-t v4 2/2] tests/i915/perf_pmu: Add second store dword for looping
Kamil Konieczny
kamil.konieczny at linux.intel.com
Thu Jul 21 08:53:22 UTC 2022
On 2022-07-21 at 06:31:26 +0200, Zbigniew Kempczyński wrote:
> On Broadwell/Braswell we observe semaphore wait isn't starting sometimes.
> It's hard to say what's the main reason of this behavior - it happens
> rare (each 2-3 months). To find out is this delayed write lets add
> additional store dword for loop condition. Add also some assertions
> to catch unexpected sw/hw behavior.
>
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/2383
>
> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> ---
Reviewed-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>
>
> v2: Add timeout to break the loop
> v3: Use debug instead warn and remove early assert (Kamil)
> ---
> tests/i915/perf_pmu.c | 42 +++++++++++++++++++++++++++++++++---------
> 1 file changed, 33 insertions(+), 9 deletions(-)
>
> diff --git a/tests/i915/perf_pmu.c b/tests/i915/perf_pmu.c
> index 39e9fc5fef..eae69aae24 100644
> --- a/tests/i915/perf_pmu.c
> +++ b/tests/i915/perf_pmu.c
> @@ -812,6 +812,12 @@ create_sema(int gem_fd, uint64_t ahnd,
> 0,
> 1,
>
> + /* Separate write for loop */
> + MI_STORE_DWORD_IMM,
> + 0,
> + 0,
> + 2,
> +
> /* Wait until the semaphore value is set to 0 [by caller] */
> MI_SEMAPHORE_WAIT | MI_SEMAPHORE_POLL | MI_SEMAPHORE_SAD_NEQ_SDD,
> 1,
> @@ -827,17 +833,22 @@ create_sema(int gem_fd, uint64_t ahnd,
> handle = gem_create(gem_fd, 4096);
> *poffset = get_offset(ahnd, handle, 4096, 0);
>
> - memset(reloc, 0, 2 * sizeof(*reloc));
> + memset(reloc, 0, 3 * sizeof(*reloc));
> reloc[0].target_handle = handle;
> reloc[0].offset = 64 + 1 * sizeof(uint32_t);
> reloc[1].target_handle = handle;
> - reloc[1].offset = 64 + 6 * sizeof(uint32_t);
> + reloc[1].offset = 64 + 5 * sizeof(uint32_t);
> + reloc[1].delta = 4;
> + reloc[2].target_handle = handle;
> + reloc[2].offset = 64 + 10 * sizeof(uint32_t);
>
> if (ahnd) {
> cs[1] = *poffset;
> cs[2] = *poffset >> 32;
> - cs[6] = *poffset;
> - cs[7] = *poffset >> 32;
> + cs[5] = *poffset + 4;
> + cs[6] = (*poffset + 4) >> 32;
> + cs[10] = *poffset;
> + cs[11] = *poffset >> 32;
> }
>
> gem_write(gem_fd, handle, 64, cs, sizeof(cs));
> @@ -856,10 +867,10 @@ __sema_busy(int gem_fd, uint64_t ahnd, int pmu, const intel_ctx_t *ctx,
> };
> uint64_t total, sema, busy;
> uint64_t start[2], val[2];
> - struct drm_i915_gem_relocation_entry reloc[2];
> + struct drm_i915_gem_relocation_entry reloc[3];
> struct drm_i915_gem_exec_object2 obj = {
> .handle = create_sema(gem_fd, ahnd, reloc, &obj.offset),
> - .relocation_count = !ahnd ? 2 : 0,
> + .relocation_count = !ahnd ? 3 : 0,
> .relocs_ptr = to_user_pointer(reloc),
> .flags = !ahnd ? 0 : EXEC_OBJECT_PINNED,
> };
> @@ -872,19 +883,32 @@ __sema_busy(int gem_fd, uint64_t ahnd, int pmu, const intel_ctx_t *ctx,
> };
> igt_spin_t *spin;
> uint32_t *map;
> + struct timespec tv = {};
> + int timeout = 3;
>
> /* Time spent being busy includes time waiting on semaphores */
> igt_assert(busy_pct >= sema_pct);
>
> gem_quiescent_gpu(gem_fd);
>
> - map = gem_mmap__device_coherent(gem_fd, obj.handle, 0, 4096, PROT_WRITE);
> + map = gem_mmap__device_coherent(gem_fd, obj.handle, 0, 4096, PROT_READ | PROT_WRITE);
> gem_execbuf(gem_fd, &eb);
> + igt_debug("[1] bo_busy = %d, map[0] = %u, map[1] = %u\n",
> + gem_bo_busy(gem_fd, obj.handle), map[0], map[1]);
> spin = igt_spin_new(gem_fd, .ahnd = ahnd, .ctx = ctx, .engine = e->flags);
>
> - /* Wait until the batch is executed and the semaphore is busy-waiting */
> - while (!READ_ONCE(*map) && gem_bo_busy(gem_fd, obj.handle))
> + /*
> + * Wait until the batch is executed and the semaphore is busy-waiting.
> + * Also stop on timeout.
> + */
> + igt_nsec_elapsed(&tv);
> + while (READ_ONCE(map[1]) != 2 && gem_bo_busy(gem_fd, obj.handle) &&
> + igt_seconds_elapsed(&tv) < timeout)
> ;
> + igt_debug("[2] bo_busy = %d, map[0] = %u, map[1] = %u, timeout: [%u/%u]\n",
> + gem_bo_busy(gem_fd, obj.handle), map[0], map[1],
> + igt_seconds_elapsed(&tv), timeout);
> + igt_assert(map[0] == 1);
> igt_assert(gem_bo_busy(gem_fd, obj.handle));
> gem_close(gem_fd, obj.handle);
>
> --
> 2.34.1
>
More information about the igt-dev
mailing list