atrace: clean up tracing option enabling
This change switches atrace to use a table-driven approach to enabling and
disabling options. It unifies how framework and kernel tracing are enabled,
and causes userland tracing options to be picked up by currently running
processes.
Change-Id: Iba2a3012ca0a67c4defdd076bce597db26e9f539
diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp
new file mode 100644
index 0000000..a4bf674
--- /dev/null
+++ b/cmds/atrace/atrace.cpp
@@ -0,0 +1,711 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/sendfile.h>
+#include <time.h>
+#include <zlib.h>
+
+#include <binder/IBinder.h>
+#include <binder/IServiceManager.h>
+#include <binder/Parcel.h>
+
+#include <cutils/properties.h>
+
+#include <utils/String8.h>
+#include <utils/Trace.h>
+
+using namespace android;
+
+#define NELEM(x) ((int) (sizeof(x) / sizeof((x)[0])))
+
+enum { MAX_SYS_FILES = 8 };
+
+const char* k_traceTagsProperty = "debug.atrace.tags.enableflags";
+
+typedef enum { OPT, REQ } requiredness ;
+
+struct TracingCategory {
+ // The name identifying the category.
+ const char* name;
+
+ // A longer description of the category.
+ const char* longname;
+
+ // The userland tracing tags that the category enables.
+ uint64_t tags;
+
+ // The fname==NULL terminated list of /sys/ files that the category
+ // enables.
+ struct {
+ // Whether the file must be writable in order to enable the tracing
+ // category.
+ requiredness required;
+
+ // The path to the enable file.
+ const char* path;
+ } sysfiles[MAX_SYS_FILES];
+};
+
+/* Tracing categories */
+static const TracingCategory k_categories[] = {
+ { "gfx", "Graphics", ATRACE_TAG_GRAPHICS, { } },
+ { "input", "Input", ATRACE_TAG_INPUT, { } },
+ { "view", "View System", ATRACE_TAG_VIEW, { } },
+ { "wm", "Window Manager", ATRACE_TAG_WINDOW_MANAGER, { } },
+ { "am", "Activity Manager", ATRACE_TAG_ACTIVITY_MANAGER, { } },
+ { "audio", "Audio", ATRACE_TAG_AUDIO, { } },
+ { "video", "Video", ATRACE_TAG_VIDEO, { } },
+ { "camera", "Camera", ATRACE_TAG_CAMERA, { } },
+ { "sched", "CPU Scheduling", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/sched/sched_switch/enable" },
+ { REQ, "/sys/kernel/debug/tracing/events/sched/sched_wakeup/enable" },
+ } },
+ { "freq", "CPU Frequency", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/power/cpu_frequency/enable" },
+ { OPT, "/sys/kernel/debug/tracing/events/power/clock_set_rate/enable" },
+ } },
+ { "membus", "Memory Bus Utilization", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/memory_bus/enable" },
+ } },
+ { "idle", "CPU Idle", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/power/cpu_idle/enable" },
+ } },
+ { "disk", "Disk I/O", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/ext4/ext4_sync_file_enter/enable" },
+ { REQ, "/sys/kernel/debug/tracing/events/ext4/ext4_sync_file_exit/enable" },
+ { REQ, "/sys/kernel/debug/tracing/events/block/block_rq_issue/enable" },
+ { REQ, "/sys/kernel/debug/tracing/events/block/block_rq_complete/enable" },
+ } },
+ { "load", "CPU Load", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/cpufreq_interactive/enable" },
+ } },
+ { "sync", "Synchronization", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/sync/enable" },
+ } },
+ { "workq", "Kernel Workqueues", 0, {
+ { REQ, "/sys/kernel/debug/tracing/events/workqueue/enable" },
+ } },
+};
+
+/* Command line options */
+static int g_traceDurationSeconds = 5;
+static bool g_traceOverwrite = false;
+static int g_traceBufferSizeKB = 2048;
+static bool g_compress = false;
+static bool g_nohup = false;
+static int g_initialSleepSecs = 0;
+
+/* Global state */
+static bool g_traceAborted = false;
+static bool g_categoryEnables[NELEM(k_categories)] = {};
+
+/* Sys file paths */
+static const char* k_traceClockPath =
+ "/sys/kernel/debug/tracing/trace_clock";
+
+static const char* k_traceBufferSizePath =
+ "/sys/kernel/debug/tracing/buffer_size_kb";
+
+static const char* k_tracingOverwriteEnablePath =
+ "/sys/kernel/debug/tracing/options/overwrite";
+
+static const char* k_tracingOnPath =
+ "/sys/kernel/debug/tracing/tracing_on";
+
+static const char* k_tracePath =
+ "/sys/kernel/debug/tracing/trace";
+
+// Check whether a file exists.
+static bool fileExists(const char* filename) {
+ return access(filename, F_OK) != -1;
+}
+
+// Check whether a file is writable.
+static bool fileIsWritable(const char* filename) {
+ return access(filename, W_OK) != -1;
+}
+
+// Write a string to a file, returning true if the write was successful.
+static bool writeStr(const char* filename, const char* str)
+{
+ int fd = open(filename, O_WRONLY);
+ if (fd == -1) {
+ fprintf(stderr, "error opening %s: %s (%d)\n", filename,
+ strerror(errno), errno);
+ return false;
+ }
+
+ bool ok = true;
+ ssize_t len = strlen(str);
+ if (write(fd, str, len) != len) {
+ fprintf(stderr, "error writing to %s: %s (%d)\n", filename,
+ strerror(errno), errno);
+ ok = false;
+ }
+
+ close(fd);
+
+ return ok;
+}
+
+// Enable or disable a kernel option by writing a "1" or a "0" into a /sys
+// file.
+static bool setKernelOptionEnable(const char* filename, bool enable)
+{
+ return writeStr(filename, enable ? "1" : "0");
+}
+
+// Check whether the category is supported on the device with the current
+// rootness. A category is supported only if all its required /sys/ files are
+// writable and if enabling the category will enable one or more tracing tags
+// or /sys/ files.
+static bool isCategorySupported(const TracingCategory& category)
+{
+ bool ok = category.tags != 0;
+ for (int i = 0; i < MAX_SYS_FILES; i++) {
+ const char* path = category.sysfiles[i].path;
+ bool req = category.sysfiles[i].required == REQ;
+ if (path != NULL) {
+ if (req) {
+ if (!fileIsWritable(path)) {
+ return false;
+ } else {
+ ok = true;
+ }
+ } else {
+ ok |= fileIsWritable(path);
+ }
+ }
+ }
+ return ok;
+}
+
+// Check whether the category would be supported on the device if the user
+// were root. This function assumes that root is able to write to any file
+// that exists. It performs the same logic as isCategorySupported, but it
+// uses file existance rather than writability in the /sys/ file checks.
+static bool isCategorySupportedForRoot(const TracingCategory& category)
+{
+ bool ok = category.tags != 0;
+ for (int i = 0; i < MAX_SYS_FILES; i++) {
+ const char* path = category.sysfiles[i].path;
+ bool req = category.sysfiles[i].required == REQ;
+ if (path != NULL) {
+ if (req) {
+ if (!fileExists(path)) {
+ return false;
+ } else {
+ ok = true;
+ }
+ } else {
+ ok |= fileExists(path);
+ }
+ }
+ }
+ return ok;
+}
+
+// Enable or disable overwriting of the kernel trace buffers. Disabling this
+// will cause tracing to stop once the trace buffers have filled up.
+static bool setTraceOverwriteEnable(bool enable)
+{
+ return setKernelOptionEnable(k_tracingOverwriteEnablePath, enable);
+}
+
+// Enable or disable kernel tracing.
+static bool setTracingEnabled(bool enable)
+{
+ return setKernelOptionEnable(k_tracingOnPath, enable);
+}
+
+// Clear the contents of the kernel trace.
+static bool clearTrace()
+{
+ int traceFD = creat(k_tracePath, 0);
+ if (traceFD == -1) {
+ fprintf(stderr, "error truncating %s: %s (%d)\n", k_tracePath,
+ strerror(errno), errno);
+ return false;
+ }
+
+ close(traceFD);
+
+ return true;
+}
+
+// Set the size of the kernel's trace buffer in kilobytes.
+static bool setTraceBufferSizeKB(int size)
+{
+ char str[32] = "1";
+ int len;
+ if (size < 1) {
+ size = 1;
+ }
+ snprintf(str, 32, "%d", size);
+ return writeStr(k_traceBufferSizePath, str);
+}
+
+// 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.
+static bool setGlobalClockEnable(bool enable)
+{
+ return writeStr(k_traceClockPath, enable ? "global" : "local");
+}
+
+// Poke all the binder-enabled processes in the system to get them to re-read
+// their system properties.
+static bool pokeBinderServices()
+{
+ sp<IServiceManager> sm = defaultServiceManager();
+ Vector<String16> services = sm->listServices();
+ for (size_t i = 0; i < services.size(); i++) {
+ sp<IBinder> obj = sm->checkService(services[i]);
+ if (obj != NULL) {
+ Parcel data;
+ if (obj->transact(IBinder::SYSPROPS_TRANSACTION, data,
+ NULL, 0) != OK) {
+ if (false) {
+ // XXX: For some reason this fails on tablets trying to
+ // poke the "phone" service. It's not clear whether some
+ // are expected to fail.
+ String8 svc(services[i]);
+ fprintf(stderr, "error poking binder service %s\n",
+ svc.string());
+ return false;
+ }
+ }
+ }
+ }
+ return true;
+}
+
+// Set the trace tags that userland tracing uses, and poke the running
+// processes to pick up the new value.
+static bool setTagsProperty(uint64_t tags)
+{
+ char buf[64];
+ snprintf(buf, 64, "%#llx", tags);
+ if (property_set(k_traceTagsProperty, buf) < 0) {
+ fprintf(stderr, "error setting trace tags system property\n");
+ return false;
+ }
+ return pokeBinderServices();
+}
+
+// Disable all /sys/ enable files.
+static bool disableKernelTraceEvents() {
+ bool ok = true;
+ for (int i = 0; i < NELEM(k_categories); i++) {
+ const TracingCategory &c = k_categories[i];
+ for (int j = 0; j < MAX_SYS_FILES; j++) {
+ const char* path = c.sysfiles[j].path;
+ if (path != NULL && fileIsWritable(path)) {
+ ok &= setKernelOptionEnable(path, false);
+ }
+ }
+ }
+ return ok;
+}
+
+// Enable tracing in the kernel.
+static bool startTrace()
+{
+ bool ok = true;
+
+ // Set up the tracing options.
+ ok &= setTraceOverwriteEnable(g_traceOverwrite);
+ ok &= setTraceBufferSizeKB(g_traceBufferSizeKB);
+ ok &= setGlobalClockEnable(true);
+
+ // Set up the tags property.
+ uint64_t tags = 0;
+ for (int i = 0; i < NELEM(k_categories); i++) {
+ if (g_categoryEnables[i]) {
+ const TracingCategory &c = k_categories[i];
+ tags |= c.tags;
+ }
+ }
+ ok &= setTagsProperty(tags);
+
+ // Disable all the sysfs enables. This is done as a separate loop from
+ // the enables to allow the same enable to exist in multiple categories.
+ ok &= disableKernelTraceEvents();
+
+ // Enable all the sysfs enables that are in an enabled category.
+ for (int i = 0; i < NELEM(k_categories); i++) {
+ if (g_categoryEnables[i]) {
+ const TracingCategory &c = k_categories[i];
+ for (int j = 0; j < MAX_SYS_FILES; j++) {
+ const char* path = c.sysfiles[j].path;
+ bool required = c.sysfiles[j].required == REQ;
+ if (path != NULL) {
+ if (fileIsWritable(path)) {
+ ok &= setKernelOptionEnable(path, true);
+ } else if (required) {
+ fprintf(stderr, "error writing file %s\n", path);
+ ok = false;
+ }
+ }
+ }
+ }
+ }
+
+ // Enable tracing.
+ ok &= setTracingEnabled(true);
+
+ return ok;
+}
+
+// Disable tracing in the kernel.
+static void stopTrace()
+{
+ // Disable tracing.
+ setTracingEnabled(false);
+
+ // Disable all tracing that we're able to.
+ disableKernelTraceEvents();
+
+ // Disable all the trace tags.
+ setTagsProperty(0);
+
+ // Set the options back to their defaults.
+ setTraceOverwriteEnable(true);
+ setGlobalClockEnable(false);
+
+ // Note that we can't reset the trace buffer size here because that would
+ // clear the trace before we've read it.
+}
+
+// Read the current kernel trace and write it to stdout.
+static void dumpTrace()
+{
+ int traceFD = open(k_tracePath, O_RDWR);
+ if (traceFD == -1) {
+ fprintf(stderr, "error opening %s: %s (%d)\n", k_tracePath,
+ strerror(errno), errno);
+ return;
+ }
+
+ if (g_compress) {
+ z_stream zs;
+ uint8_t *in, *out;
+ int result, flush;
+
+ bzero(&zs, sizeof(zs));
+ result = deflateInit(&zs, Z_DEFAULT_COMPRESSION);
+ if (result != Z_OK) {
+ fprintf(stderr, "error initializing zlib: %d\n", result);
+ close(traceFD);
+ return;
+ }
+
+ const size_t bufSize = 64*1024;
+ in = (uint8_t*)malloc(bufSize);
+ out = (uint8_t*)malloc(bufSize);
+ flush = Z_NO_FLUSH;
+
+ zs.next_out = out;
+ zs.avail_out = bufSize;
+
+ do {
+
+ if (zs.avail_in == 0) {
+ // More input is needed.
+ result = read(traceFD, in, bufSize);
+ if (result < 0) {
+ fprintf(stderr, "error reading trace: %s (%d)\n",
+ strerror(errno), errno);
+ result = Z_STREAM_END;
+ break;
+ } else if (result == 0) {
+ flush = Z_FINISH;
+ } else {
+ zs.next_in = in;
+ zs.avail_in = result;
+ }
+ }
+
+ if (zs.avail_out == 0) {
+ // Need to write the output.
+ result = write(STDOUT_FILENO, out, bufSize);
+ if ((size_t)result < bufSize) {
+ fprintf(stderr, "error writing deflated trace: %s (%d)\n",
+ strerror(errno), errno);
+ result = Z_STREAM_END; // skip deflate error message
+ zs.avail_out = bufSize; // skip the final write
+ break;
+ }
+ zs.next_out = out;
+ zs.avail_out = bufSize;
+ }
+
+ } while ((result = deflate(&zs, flush)) == Z_OK);
+
+ if (result != Z_STREAM_END) {
+ fprintf(stderr, "error deflating trace: %s\n", zs.msg);
+ }
+
+ if (zs.avail_out < bufSize) {
+ size_t bytes = bufSize - zs.avail_out;
+ result = write(STDOUT_FILENO, out, bytes);
+ if ((size_t)result < bytes) {
+ fprintf(stderr, "error writing deflated trace: %s (%d)\n",
+ strerror(errno), errno);
+ }
+ }
+
+ result = deflateEnd(&zs);
+ if (result != Z_OK) {
+ fprintf(stderr, "error cleaning up zlib: %d\n", result);
+ }
+
+ free(in);
+ free(out);
+ } else {
+ ssize_t sent = 0;
+ while ((sent = sendfile(STDOUT_FILENO, traceFD, NULL, 64*1024*1024)) > 0);
+ if (sent == -1) {
+ fprintf(stderr, "error dumping trace: %s (%d)\n", strerror(errno),
+ errno);
+ }
+ }
+
+ close(traceFD);
+}
+
+static void handleSignal(int signo)
+{
+ if (!g_nohup) {
+ g_traceAborted = true;
+ }
+}
+
+static void registerSigHandler()
+{
+ struct sigaction sa;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = 0;
+ sa.sa_handler = handleSignal;
+ sigaction(SIGHUP, &sa, NULL);
+ sigaction(SIGINT, &sa, NULL);
+ sigaction(SIGQUIT, &sa, NULL);
+ sigaction(SIGTERM, &sa, NULL);
+}
+
+static bool setCategoryEnable(const char* name, bool enable)
+{
+ for (int i = 0; i < NELEM(k_categories); i++) {
+ const TracingCategory& c = k_categories[i];
+ if (strcmp(name, c.name) == 0) {
+ if (isCategorySupported(c)) {
+ g_categoryEnables[i] = enable;
+ return true;
+ } else {
+ if (isCategorySupportedForRoot(c)) {
+ fprintf(stderr, "error: category \"%s\" requires root "
+ "privileges.\n", name);
+ } else {
+ fprintf(stderr, "error: category \"%s\" is not supported "
+ "on this device.\n", name);
+ }
+ return false;
+ }
+ }
+ }
+ fprintf(stderr, "error: unknown tracing category \"%s\"\n", name);
+ return false;
+}
+
+static void listSupportedCategories()
+{
+ for (int i = 0; i < NELEM(k_categories); i++) {
+ const TracingCategory& c = k_categories[i];
+ if (isCategorySupported(c)) {
+ printf(" %10s - %s\n", c.name, c.longname);
+ }
+ }
+}
+
+// Print the command usage help to stderr.
+static void showHelp(const char *cmd)
+{
+ fprintf(stderr, "usage: %s [options] [categories...]\n", cmd);
+ fprintf(stderr, "options include:\n"
+ " -b N use a trace buffer size of N KB\n"
+ " -c trace into a circular buffer\n"
+ " -n ignore signals\n"
+ " -s N sleep for N seconds before tracing [default 0]\n"
+ " -t N trace for N seconds [defualt 5]\n"
+ " -z compress the trace dump\n"
+ " --async_start start circular trace and return immediatly\n"
+ " --async_dump dump the current contents of circular trace buffer\n"
+ " --async_stop stop tracing and dump the current contents of circular\n"
+ " trace buffer\n"
+ );
+}
+
+int main(int argc, char **argv)
+{
+ bool async = false;
+ bool traceStart = true;
+ bool traceStop = true;
+ bool traceDump = true;
+
+ if (argc == 2 && 0 == strcmp(argv[1], "--help")) {
+ showHelp(argv[0]);
+ exit(0);
+ }
+
+ for (;;) {
+ int ret;
+ int option_index = 0;
+ static struct option long_options[] = {
+ {"async_start", no_argument, 0, 0 },
+ {"async_stop", no_argument, 0, 0 },
+ {"async_dump", no_argument, 0, 0 },
+ {"list_categories", no_argument, 0, 0 },
+ { 0, 0, 0, 0 }
+ };
+
+ ret = getopt_long(argc, argv, "b:cns:t:z",
+ long_options, &option_index);
+
+ if (ret < 0) {
+ for (int i = optind; i < argc; i++) {
+ if (!setCategoryEnable(argv[i], true)) {
+ fprintf(stderr, "error enabling tracing category \"%s\"\n", argv[i]);
+ exit(1);
+ }
+ }
+ break;
+ }
+
+ switch(ret) {
+ case 'b':
+ g_traceBufferSizeKB = atoi(optarg);
+ break;
+
+ case 'c':
+ g_traceOverwrite = true;
+ break;
+
+ case 'n':
+ g_nohup = true;
+ break;
+
+ case 's':
+ g_initialSleepSecs = atoi(optarg);
+ break;
+
+ case 't':
+ g_traceDurationSeconds = atoi(optarg);
+ break;
+
+ case 'z':
+ g_compress = true;
+ break;
+
+ case 0:
+ if (!strcmp(long_options[option_index].name, "async_start")) {
+ async = true;
+ traceStop = false;
+ traceDump = false;
+ g_traceOverwrite = true;
+ } else if (!strcmp(long_options[option_index].name, "async_stop")) {
+ async = true;
+ traceStop = false;
+ } else if (!strcmp(long_options[option_index].name, "async_dump")) {
+ async = true;
+ traceStart = false;
+ traceStop = false;
+ } else if (!strcmp(long_options[option_index].name, "list_categories")) {
+ listSupportedCategories();
+ exit(0);
+ }
+ break;
+
+ default:
+ fprintf(stderr, "\n");
+ showHelp(argv[0]);
+ exit(-1);
+ break;
+ }
+ }
+
+ registerSigHandler();
+
+ if (g_initialSleepSecs > 0) {
+ sleep(g_initialSleepSecs);
+ }
+
+ bool ok = startTrace();
+
+ if (ok && traceStart) {
+ printf("capturing trace...");
+ fflush(stdout);
+
+ // We clear the trace after starting it because tracing gets enabled for
+ // each CPU individually in the kernel. Having the beginning of the trace
+ // contain entries from only one CPU can cause "begin" entries without a
+ // matching "end" entry to show up if a task gets migrated from one CPU to
+ // another.
+ ok = clearTrace();
+
+ if (ok && !async) {
+ // Sleep to allow the trace to be captured.
+ struct timespec timeLeft;
+ timeLeft.tv_sec = g_traceDurationSeconds;
+ timeLeft.tv_nsec = 0;
+ do {
+ if (g_traceAborted) {
+ break;
+ }
+ } while (nanosleep(&timeLeft, &timeLeft) == -1 && errno == EINTR);
+ }
+ }
+
+ // Stop the trace and restore the default settings.
+ if (traceStop)
+ stopTrace();
+
+ if (ok && traceDump) {
+ if (!g_traceAborted) {
+ printf(" done\nTRACE:\n");
+ fflush(stdout);
+ dumpTrace();
+ } else {
+ printf("\ntrace aborted.\n");
+ fflush(stdout);
+ }
+ clearTrace();
+ } else if (!ok) {
+ fprintf(stderr, "unable to start tracing\n");
+ }
+
+ // Reset the trace buffer size to 1.
+ if (traceStop)
+ setTraceBufferSizeKB(1);
+
+ return g_traceAborted ? 1 : 0;
+}