/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace android; #define NELEM(x) ((int) (sizeof(x) / sizeof((x)[0]))) enum { MAX_SYS_FILES = 10 }; const char* k_traceTagsProperty = "debug.atrace.tags.enableflags"; const char* k_traceAppCmdlineProperty = "debug.atrace.app_cmdlines"; 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, { } }, { "webview", "WebView", ATRACE_TAG_WEBVIEW, { } }, { "wm", "Window Manager", ATRACE_TAG_WINDOW_MANAGER, { } }, { "am", "Activity Manager", ATRACE_TAG_ACTIVITY_MANAGER, { } }, { "sm", "Sync Manager", ATRACE_TAG_SYNC_MANAGER, { } }, { "audio", "Audio", ATRACE_TAG_AUDIO, { } }, { "video", "Video", ATRACE_TAG_VIDEO, { } }, { "camera", "Camera", ATRACE_TAG_CAMERA, { } }, { "hal", "Hardware Modules", ATRACE_TAG_HAL, { } }, { "app", "Application", ATRACE_TAG_APP, { } }, { "res", "Resource Loading", ATRACE_TAG_RESOURCES, { } }, { "dalvik", "Dalvik VM", ATRACE_TAG_DALVIK, { } }, { "rs", "RenderScript", ATRACE_TAG_RS, { } }, { "bionic", "Bionic C Library", ATRACE_TAG_BIONIC, { } }, { "power", "Power Management", ATRACE_TAG_POWER, { } }, { "sched", "CPU Scheduling", 0, { { REQ, "/sys/kernel/debug/tracing/events/sched/sched_switch/enable" }, { REQ, "/sys/kernel/debug/tracing/events/sched/sched_wakeup/enable" }, } }, { "irq", "IRQ Events", 0, { { REQ, "/sys/kernel/debug/tracing/events/irq/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, { { OPT, "/sys/kernel/debug/tracing/events/f2fs/f2fs_sync_file_enter/enable" }, { OPT, "/sys/kernel/debug/tracing/events/f2fs/f2fs_sync_file_exit/enable" }, { OPT, "/sys/kernel/debug/tracing/events/f2fs/f2fs_write_begin/enable" }, { OPT, "/sys/kernel/debug/tracing/events/f2fs/f2fs_write_end/enable" }, { OPT, "/sys/kernel/debug/tracing/events/ext4/ext4_da_write_begin/enable" }, { OPT, "/sys/kernel/debug/tracing/events/ext4/ext4_da_write_end/enable" }, { OPT, "/sys/kernel/debug/tracing/events/ext4/ext4_sync_file_enter/enable" }, { OPT, "/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" }, } }, { "mmc", "eMMC commands", 0, { { REQ, "/sys/kernel/debug/tracing/events/mmc/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" }, } }, { "memreclaim", "Kernel Memory Reclaim", 0, { { REQ, "/sys/kernel/debug/tracing/events/vmscan/mm_vmscan_direct_reclaim_begin/enable" }, { REQ, "/sys/kernel/debug/tracing/events/vmscan/mm_vmscan_direct_reclaim_end/enable" }, { REQ, "/sys/kernel/debug/tracing/events/vmscan/mm_vmscan_kswapd_wake/enable" }, { REQ, "/sys/kernel/debug/tracing/events/vmscan/mm_vmscan_kswapd_sleep/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; static const char* g_kernelTraceFuncs = NULL; static const char* g_debugAppCmdLine = ""; /* 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_currentTracerPath = "/sys/kernel/debug/tracing/current_tracer"; static const char* k_printTgidPath = "/sys/kernel/debug/tracing/options/print-tgid"; static const char* k_funcgraphAbsTimePath = "/sys/kernel/debug/tracing/options/funcgraph-abstime"; static const char* k_funcgraphCpuPath = "/sys/kernel/debug/tracing/options/funcgraph-cpu"; static const char* k_funcgraphProcPath = "/sys/kernel/debug/tracing/options/funcgraph-proc"; static const char* k_funcgraphFlatPath = "/sys/kernel/debug/tracing/options/funcgraph-flat"; static const char* k_funcgraphDurationPath = "/sys/kernel/debug/tracing/options/funcgraph-duration"; static const char* k_ftraceFilterPath = "/sys/kernel/debug/tracing/set_ftrace_filter"; 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; } // Truncate a file. static bool truncateFile(const char* path) { // This uses creat rather than truncate because some of the debug kernel // device nodes (e.g. k_ftraceFilterPath) currently aren't changed by // calls to truncate, but they are cleared by calls to creat. int traceFD = creat(path, 0); if (traceFD == -1) { fprintf(stderr, "error truncating %s: %s (%d)\n", path, strerror(errno), errno); return false; } close(traceFD); return true; } static bool _writeStr(const char* filename, const char* str, int flags) { int fd = open(filename, flags); 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; } // Write a string to a file, returning true if the write was successful. static bool writeStr(const char* filename, const char* str) { return _writeStr(filename, str, O_WRONLY); } // Append a string to a file, returning true if the write was successful. static bool appendStr(const char* filename, const char* str) { return _writeStr(filename, str, O_APPEND|O_WRONLY); } // 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() { return truncateFile(k_tracePath); } // 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); } // Read the trace_clock sysfs file and return true if it matches the requested // value. The trace_clock file format is: // local [global] counter uptime perf static bool isTraceClock(const char *mode) { int fd = open(k_traceClockPath, O_RDONLY); if (fd == -1) { fprintf(stderr, "error opening %s: %s (%d)\n", k_traceClockPath, strerror(errno), errno); return false; } char buf[4097]; ssize_t n = read(fd, buf, 4096); close(fd); if (n == -1) { fprintf(stderr, "error reading %s: %s (%d)\n", k_traceClockPath, strerror(errno), errno); return false; } buf[n] = '\0'; char *start = strchr(buf, '['); if (start == NULL) { return false; } start++; char *end = strchr(start, ']'); if (end == NULL) { return false; } *end = '\0'; 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. // 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) { const char *clock = enable ? "global" : "local"; if (isTraceClock(clock)) { return true; } return writeStr(k_traceClockPath, clock); } static bool setPrintTgidEnableIfPresent(bool enable) { if (fileExists(k_printTgidPath)) { return setKernelOptionEnable(k_printTgidPath, enable); } return true; } // Poke all the binder-enabled processes in the system to get them to re-read // their system properties. static bool pokeBinderServices() { sp sm = defaultServiceManager(); Vector services = sm->listServices(); for (size_t i = 0; i < services.size(); i++) { sp 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, "%#" PRIx64, tags); if (property_set(k_traceTagsProperty, buf) < 0) { fprintf(stderr, "error setting trace tags system property\n"); return false; } return true; } // Set the system property that indicates which apps should perform // application-level tracing. static bool setAppCmdlineProperty(const char* cmdline) { if (property_set(k_traceAppCmdlineProperty, cmdline) < 0) { fprintf(stderr, "error setting trace app system property\n"); return false; } return true; } // 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; } // Verify that the comma separated list of functions are being traced by the // kernel. static bool verifyKernelTraceFuncs(const char* funcs) { int fd = open(k_ftraceFilterPath, O_RDONLY); if (fd == -1) { fprintf(stderr, "error opening %s: %s (%d)\n", k_ftraceFilterPath, strerror(errno), errno); return false; } char buf[4097]; ssize_t n = read(fd, buf, 4096); close(fd); if (n == -1) { fprintf(stderr, "error reading %s: %s (%d)\n", k_ftraceFilterPath, strerror(errno), errno); return false; } buf[n] = '\0'; String8 funcList = String8::format("\n%s", buf); // Make sure that every function listed in funcs is in the list we just // read from the kernel. bool ok = true; char* myFuncs = strdup(funcs); char* func = strtok(myFuncs, ","); while (func) { String8 fancyFunc = String8::format("\n%s\n", func); bool found = funcList.find(fancyFunc.string(), 0) >= 0; if (!found || func[0] == '\0') { fprintf(stderr, "error: \"%s\" is not a valid kernel function " "to trace.\n", func); ok = false; } func = strtok(NULL, ","); } free(myFuncs); return ok; } // Set the comma separated list of functions that the kernel is to trace. static bool setKernelTraceFuncs(const char* funcs) { bool ok = true; if (funcs == NULL || funcs[0] == '\0') { // Disable kernel function tracing. if (fileIsWritable(k_currentTracerPath)) { ok &= writeStr(k_currentTracerPath, "nop"); } if (fileIsWritable(k_ftraceFilterPath)) { ok &= truncateFile(k_ftraceFilterPath); } } else { // Enable kernel function tracing. ok &= writeStr(k_currentTracerPath, "function_graph"); ok &= setKernelOptionEnable(k_funcgraphAbsTimePath, true); ok &= setKernelOptionEnable(k_funcgraphCpuPath, true); ok &= setKernelOptionEnable(k_funcgraphProcPath, true); ok &= setKernelOptionEnable(k_funcgraphFlatPath, true); // Set the requested filter functions. ok &= truncateFile(k_ftraceFilterPath); char* myFuncs = strdup(funcs); char* func = strtok(myFuncs, ","); while (func) { ok &= appendStr(k_ftraceFilterPath, func); func = strtok(NULL, ","); } free(myFuncs); // Verify that the set functions are being traced. if (ok) { ok &= verifyKernelTraceFuncs(funcs); } } return ok; } // Set all the kernel tracing settings to the desired state for this trace // capture. static bool setUpTrace() { bool ok = true; // Set up the tracing options. ok &= setTraceOverwriteEnable(g_traceOverwrite); ok &= setTraceBufferSizeKB(g_traceBufferSizeKB); ok &= setGlobalClockEnable(true); ok &= setPrintTgidEnableIfPresent(true); ok &= setKernelTraceFuncs(g_kernelTraceFuncs); // 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); ok &= setAppCmdlineProperty(g_debugAppCmdLine); ok &= pokeBinderServices(); // 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; } } } } } return ok; } // Reset all the kernel tracing settings to their default state. static void cleanUpTrace() { // Disable all tracing that we're able to. disableKernelTraceEvents(); // Reset the system properties. setTagsProperty(0); setAppCmdlineProperty(""); pokeBinderServices(); // Set the options back to their defaults. setTraceOverwriteEnable(true); setTraceBufferSizeKB(1); setGlobalClockEnable(false); setPrintTgidEnableIfPresent(false); setKernelTraceFuncs(NULL); } // Enable tracing in the kernel. static bool startTrace() { return setTracingEnabled(true); } // Disable tracing in the kernel. static void stopTrace() { setTracingEnabled(false); } // 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" " -a appname enable app-level tracing for a comma " "separated list of cmdlines\n" " -b N use a trace buffer size of N KB\n" " -c trace into a circular buffer\n" " -k fname,... trace the listed kernel functions\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" " --list_categories\n" " list the available tracing categories\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, "a:b:ck:ns: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 'a': g_debugAppCmdLine = optarg; break; case 'b': g_traceBufferSizeKB = atoi(optarg); break; case 'c': g_traceOverwrite = true; break; case 'k': g_kernelTraceFuncs = optarg; 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 = true; ok &= setUpTrace(); 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) cleanUpTrace(); return g_traceAborted ? 1 : 0; }