Merge "Set the atrace clock to boot when possible and mono otherwise." into oc-dev (e721536e) · Commits · e / os / android_frameworks_native

cmds/atrace/atrace.cpp

+33 −9

Original line number	Diff line number	Diff line
		@@ -450,8 +450,8 @@ static bool isTraceClock(const char *mode)
		return false;
		}

		char buf[4097];
		ssize_t n = read(fd, buf, 4096);
		char buf[100];
		ssize_t n = read(fd, buf, 99);
		close(fd);
		if (n == -1) {
		fprintf(stderr, "error reading %s: %s (%d)\n", k_traceClockPath,
		@@ -475,13 +475,38 @@ static bool isTraceClock(const char *mode)
		return strcmp(mode, start) == 0;
		}

		// Enable or disable the kernel's use of the global clock. Disabling the global
		// clock will result in the kernel using a per-CPU local clock.
		// Read the trace_clock sysfs file and return true if it contains the requested
		// value. The trace_clock file format is:
		// local [global] counter uptime perf
		static bool traceClockContains(const char *mode)
		{
		int fd = open((g_traceFolder + k_traceClockPath).c_str(), O_RDONLY);
		if (fd == -1) {
		fprintf(stderr, "error opening %s: %s (%d)\n", k_traceClockPath,
		strerror(errno), errno);
		return false;
		}

		char buf[100];
		ssize_t n = read(fd, buf, 99);
		close(fd);
		if (n == -1) {
		fprintf(stderr, "error reading %s: %s (%d)\n", k_traceClockPath,
		strerror(errno), errno);
		return false;
		}
		buf[n] = '\0';

		return strstr(buf, mode) != NULL;
		}

		// Set the clock to the best available option while tracing. Use 'boot' if it's
		// available; otherwise, use 'mono'.
		// Any write to the trace_clock sysfs file will reset the buffer, so only
		// update it if the requested value is not the current value.
		static bool setGlobalClockEnable(bool enable)
		static bool setClock()
		{
		const char *clock = enable ? "global" : "local";
		const char* clock = traceClockContains("boot") ? "boot" : "mono";

		if (isTraceClock(clock)) {
		return true;
		@@ -783,7 +808,7 @@ static bool setUpTrace()
		ok &= setCategoriesEnableFromFile(g_categoriesFile);
		ok &= setTraceOverwriteEnable(g_traceOverwrite);
		ok &= setTraceBufferSizeKB(g_traceBufferSizeKB);
		ok &= setGlobalClockEnable(true);
		ok &= setClock();
		ok &= setPrintTgidEnableIfPresent(true);
		ok &= setKernelTraceFuncs(g_kernelTraceFuncs);

		@@ -859,7 +884,6 @@ static void cleanUpTrace()
		// Set the options back to their defaults.
		setTraceOverwriteEnable(true);
		setTraceBufferSizeKB(1);
		setGlobalClockEnable(false);
		setPrintTgidEnableIfPresent(false);
		setKernelTraceFuncs(NULL);
		}
		@@ -1210,7 +1234,7 @@ int main(int argc, char **argv)

		if (ok && traceStart) {
		if (!traceStream) {
		printf("capturing trace...");
		printf("capturing trace...\n");
		fflush(stdout);
		}

cmds/atrace/atrace.rc

+4 −0

Original line number	Diff line number	Diff line
		@@ -124,6 +124,10 @@ on post-fs
		write /sys/kernel/debug/tracing/tracing_on 0
		write /sys/kernel/tracing/tracing_on 0

		# Set the trace clock to boot if it exists, falling back to mono if not.
		write /d/tracing/trace_clock mono
		write /d/tracing/trace_clock boot

		# Allow only the shell group to read and truncate the kernel trace.
		chown root shell /sys/kernel/debug/tracing/trace
		chown root shell /sys/kernel/tracing/trace