Merge branch 'github/fork/emersion/tracing' into 'master'

Add kernel tracing instrumentation

See merge request wlroots/wlroots!2791

backend/drm/drm.c

@@ -27,6 +27,7 @@
 #include "render/color.h"
 #include "types/wlr_output.h"
 #include "util/env.h"
+#include "util/trace.h"
 #include "config.h"
 
 #if HAVE_LIBLIFTOFF
@@ -615,6 +616,8 @@ static bool drm_commit(struct wlr_drm_backend *drm,
 	// Disallow atomic-only flags
 	assert((flags & ~DRM_MODE_PAGE_FLIP_FLAGS) == 0);
 
+	wlr_trace("drm_commit");
+
 	struct wlr_drm_page_flip *page_flip = NULL;
 	if (flags & DRM_MODE_PAGE_FLIP_EVENT) {
 		page_flip = drm_page_flip_create(drm, state);
@@ -998,7 +1001,11 @@ static bool drm_connector_test(struct wlr_output *output,
 static bool drm_connector_commit(struct wlr_output *output,
 		const struct wlr_output_state *state) {
 	struct wlr_drm_connector *conn = get_drm_connector_from_output(output);
-	return drm_connector_commit_state(conn, state, false);
+	struct wlr_trace_ctx trace_ctx;
+	wlr_trace_begin_ctx(&trace_ctx, "drm_connector_commit");
+	bool ok = drm_connector_commit_state(conn, state, false);
+	wlr_trace_end_ctx(&trace_ctx, "drm_connector_commit");
+	return ok;
 }
 
 size_t drm_crtc_get_gamma_lut_size(struct wlr_drm_backend *drm,
@@ -1989,6 +1996,8 @@ static void handle_page_flip(int fd, unsigned seq,
 		unsigned tv_sec, unsigned tv_usec, unsigned crtc_id, void *data) {
 	struct wlr_drm_page_flip *page_flip = data;
 
+	wlr_trace("drm_page_flip_uevent");
+
 	struct wlr_drm_connector *conn = drm_page_flip_pop(page_flip, crtc_id);
 	if (conn != NULL) {
 		conn->pending_page_flip = NULL;

include/util/trace.h

@@ -0,0 +1,17 @@
+#ifndef UTIL_TRACE_H
+#define UTIL_TRACE_H
+
+#include <stdint.h>
+#include <wlr/util/log.h>
+
+void wlr_trace(const char *format, ...) _WLR_ATTRIB_PRINTF(1, 2);
+void wlr_vtrace(const char *format, va_list args) _WLR_ATTRIB_PRINTF(1, 0);
+
+struct wlr_trace_ctx {
+	uint32_t seq;
+};
+
+void wlr_trace_begin_ctx(struct wlr_trace_ctx *ctx, const char *format, ...) _WLR_ATTRIB_PRINTF(2, 3);
+void wlr_trace_end_ctx(struct wlr_trace_ctx *ctx, const char *format, ...) _WLR_ATTRIB_PRINTF(2, 3);
+
+#endif

types/wlr_linux_drm_syncobj_v1.c

@@ -11,6 +11,7 @@
 #include <xf86drm.h>
 #include "config.h"
 #include "linux-drm-syncobj-v1-protocol.h"
+#include "util/trace.h"
 
 #define LINUX_DRM_SYNCOBJ_V1_VERSION 1
 
@@ -214,6 +215,9 @@ static void surface_commit_handle_surface_destroy(struct wl_listener *listener,
 // Block the surface commit until the fence materializes
 static bool lock_surface_commit(struct wlr_linux_drm_syncobj_surface_v1 *surface,
 		struct wlr_drm_syncobj_timeline *timeline, uint64_t point) {
+	wlr_trace("linux_drm_syncobj_v1_commit (handle=%"PRIu32" point=%"PRIu64")",
+		timeline->handle, point);
+
 	uint32_t flags = DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE;
 
 	bool already_materialized = false;
@@ -475,6 +479,9 @@ struct release_signaller {
 static void release_signaller_handle_buffer_release(struct wl_listener *listener, void *data) {
 	struct release_signaller *signaller = wl_container_of(listener, signaller, buffer_release);
 
+	wlr_trace("linux_drm_syncobj_v1_release (handle=%"PRIu32" point=%"PRIu64")",
+		signaller->timeline->handle, signaller->point);
+
 	if (drmSyncobjTimelineSignal(signaller->timeline->drm_fd, &signaller->timeline->handle,
 			&signaller->point, 1) != 0) {
 		wlr_log(WLR_ERROR, "drmSyncobjTimelineSignal() failed");

util/meson.build

@@ -13,6 +13,7 @@ wlr_files += files(
 	'shm.c',
 	'time.c',
 	'token.c',
+	'trace.c',
 	'transform.c',
 	'utf8.c',
 	'version.c',

util/trace.c

@@ -0,0 +1,58 @@
+#include <inttypes.h>
+#include <stdio.h>
+#include "util/trace.h"
+
+static bool trace_initialized = false;
+static FILE *trace_file = NULL;
+static uint32_t prev_ctx = 0;
+
+void wlr_vtrace(const char *fmt, va_list args) {
+	if (!trace_initialized) {
+		trace_initialized = true;
+		trace_file = fopen("/sys/kernel/tracing/trace_marker", "w");
+		if (trace_file != NULL) {
+			wlr_log(WLR_INFO, "Kernel tracing is enabled");
+		}
+	}
+
+	if (trace_file == NULL) {
+		return;
+	}
+
+	vfprintf(trace_file, fmt, args);
+	fprintf(trace_file, "\n");
+	fflush(trace_file);
+}
+
+void wlr_trace(const char *fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	wlr_vtrace(fmt, args);
+	va_end(args);
+}
+
+void wlr_trace_begin_ctx(struct wlr_trace_ctx *ctx, const char *fmt, ...) {
+	*ctx = (struct wlr_trace_ctx){
+		.seq = prev_ctx++,
+	};
+
+	static char new_fmt[512];
+	snprintf(new_fmt, sizeof(new_fmt), "%s (begin_ctx=%"PRIu32")", fmt, ctx->seq);
+
+	va_list args;
+	va_start(args, fmt);
+	wlr_vtrace(new_fmt, args);
+	va_end(args);
+}
+
+void wlr_trace_end_ctx(struct wlr_trace_ctx *ctx, const char *fmt, ...) {
+	static char new_fmt[512];
+	snprintf(new_fmt, sizeof(new_fmt), "%s (end_ctx=%"PRIu32")", fmt, ctx->seq);
+
+	va_list args;
+	va_start(args, fmt);
+	wlr_vtrace(new_fmt, args);
+	va_end(args);
+
+	ctx->seq = 0;
+}