benchmarks: Record and replay calls to EXECBUFFER2

This slightly idealises the behaviour of clients with the aim of
measuring the kernel overhead of different workloads. This test focuses
on the cost of relocating batchbuffers.

A trace file is generated with an LD_PRELOAD intercept around
execbuffer, which we can then replay at our leisure. The replay replaces
the real buffers with a set of empty ones so the only thing that the
kernel has to do is parse the relocations. but without a real workload
we lose the impact of having to rewrite active buffers.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 257 insertions, 0 deletions

diff --git a/benchmarks/gem_exec_trace.c b/benchmarks/gem_exec_trace.c
new file mode 100644
index 00000000..a9e3eff1
--- /dev/null
+++ b/benchmarks/gem_exec_trace.c
@@ -0,0 +1,257 @@
+/*
+ * Copyright © 2011 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.
+ *
+ * Authors:
+ *    Chris Wilson <chris@chris-wilson.co.uk>
+ *
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include "drm.h"
+#include "ioctl_wrappers.h"
+#include "drmtest.h"
+#include "intel_io.h"
+#include "igt_stats.h"
+
+enum {
+	ADD_BO = 0,
+	DEL_BO,
+	EXEC,
+};
+
+struct trace_add_bo {
+	uint32_t handle;
+	uint64_t size;
+} __attribute__((packed));
+
+struct trace_del_bo {
+	uint32_t handle;
+} __attribute__((packed));
+
+struct trace_exec {
+	uint32_t object_count;
+	uint64_t flags;
+} __attribute__((packed));
+struct trace_exec_object {
+	uint32_t handle;
+	uint32_t relocation_count;
+	uint64_t alignment;
+	uint64_t flags;
+	uint64_t rsvd1;
+	uint64_t rsvd2;
+} __attribute__((packed));
+struct trace_exec_relocation {
+	uint32_t target_handle;
+	uint32_t delta;
+	uint64_t offset;
+	uint32_t read_domains;
+	uint32_t write_domain;
+} __attribute__((packed));
+
+static double elapsed(const struct timespec *start, const struct timespec *end)
+{
+	return 1e3*(end->tv_sec - start->tv_sec) + 1e-6*(end->tv_nsec - start->tv_nsec);
+}
+
+int fd;
+
+struct bo {
+	uint32_t handle;
+	uint64_t offset;
+
+	struct drm_i915_gem_relocation_entry *relocs;
+	uint32_t max_relocs;
+} *bo, **offsets;
+int num_bo;
+
+struct drm_i915_gem_exec_object2 *exec_objects;
+int max_objects;
+
+static void *add_bo(void *ptr)
+{
+	struct trace_add_bo *t = ptr;
+	uint32_t bb = 0xa << 23;
+
+	if (t->handle > num_bo) {
+		num_bo = (t->handle + 4095) & -4096;
+		bo = realloc(bo, sizeof(*bo)*num_bo);
+	}
+
+	bo[t->handle].handle = gem_create(fd, t->size);
+	gem_write(fd, bo[t->handle].handle, 0, &bb, sizeof(bb));
+
+	return t + 1;
+}
+
+static void *del_bo(void *ptr)
+{
+	struct trace_del_bo *t = ptr;
+
+	gem_close(fd, bo[t->handle].handle);
+	bo[t->handle].handle = 0;
+
+	free(bo[t->handle].relocs);
+	bo[t->handle].relocs = NULL;
+	bo[t->handle].max_relocs = 0;
+
+	return t + 1;
+}
+
+static void *exec(void *ptr)
+{
+	struct trace_exec *t = ptr;
+	struct drm_i915_gem_execbuffer2 eb;
+	uint32_t i, j;
+
+	memset(&eb, 0, sizeof(eb));
+	eb.buffer_count = t->object_count;
+	eb.flags = t->flags & ~I915_EXEC_RING_MASK;
+
+	if (t->object_count > max_objects) {
+		free(exec_objects);
+		free(offsets);
+
+		max_objects = ALIGN(t->object_count, 4096);
+
+		exec_objects = malloc(max_objects*sizeof(*exec_objects));
+		offsets = malloc(max_objects*sizeof(*offsets));
+	}
+	eb.buffers_ptr = (uintptr_t)exec_objects;
+
+	ptr = t + 1;
+	for (i = 0; i < t->object_count; i++) {
+		struct drm_i915_gem_relocation_entry *relocs;
+		struct trace_exec_object *to = ptr;
+		ptr = to + 1;
+
+		offsets[i] = &bo[to->handle];
+
+		exec_objects[i].handle = bo[to->handle].handle;
+		exec_objects[i].offset = bo[to->handle].offset;
+		exec_objects[i].alignment = to->alignment;
+		exec_objects[i].flags = to->flags;
+		exec_objects[i].rsvd1 = to->rsvd1;
+		exec_objects[i].rsvd2 = to->rsvd2;
+
+		exec_objects[i].relocation_count = to->relocation_count;
+		if (!to->relocation_count)
+			continue;
+
+		if (to->relocation_count > bo[to->handle].max_relocs) {
+			free(bo[to->handle].relocs);
+
+			bo[to->handle].max_relocs = ALIGN(to->relocation_count, 128);
+			bo[to->handle].relocs = malloc(sizeof(*bo[to->handle].relocs)*bo[to->handle].max_relocs);
+		}
+		relocs = bo[to->handle].relocs;
+		exec_objects[i].relocs_ptr = (uintptr_t)relocs;
+
+		for (j = 0; j < to->relocation_count; j++) {
+			struct trace_exec_relocation *tr = ptr;
+			ptr = tr + 1;
+
+			if (t->flags & I915_EXEC_HANDLE_LUT) {
+				uint32_t handle;
+
+				relocs[j].target_handle = tr->target_handle;
+
+				handle = exec_objects[tr->target_handle].handle;
+				relocs[j].presumed_offset = bo[handle].offset;
+			} else {
+				relocs[j].target_handle = bo[tr->target_handle].handle;
+				relocs[j].presumed_offset = bo[tr->target_handle].offset;
+			}
+			relocs[j].delta = tr->delta;
+			relocs[j].offset = tr->offset;
+			relocs[j].read_domains = tr->read_domains;
+			relocs[j].write_domain = tr->write_domain;
+		}
+	}
+
+	gem_execbuf(fd, &eb);
+
+	for (i = 0; i < t->object_count; i++)
+		offsets[i]->offset = exec_objects[i].offset;
+
+	return ptr;
+}
+
+static void replay(const char *filename)
+{
+	struct timespec t_start, t_end;
+	struct stat st;
+	uint8_t *ptr, *end;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return;
+
+	if (fstat(fd, &st) < 0)
+		return;
+
+	ptr = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+	close(fd);
+
+	end = ptr + st.st_size;
+	fd = drm_open_any();
+
+	clock_gettime(CLOCK_MONOTONIC, &t_start);
+	do {
+		switch (*ptr++) {
+		case ADD_BO:
+			ptr = add_bo(ptr);
+			break;
+		case DEL_BO:
+			ptr = del_bo(ptr);
+			break;
+		case EXEC:
+			ptr = exec(ptr);
+			break;
+		}
+	} while (ptr < end);
+	clock_gettime(CLOCK_MONOTONIC, &t_end);
+	close(fd);
+
+	printf("%s: %.3f\n", filename, elapsed(&t_start, &t_end));
+}
+
+int main(int argc, char **argv)
+{
+	int i;
+
+	for (i = 1; i < argc; i++)
+		replay(argv[i]);
+
+	return 0;
+}