Merge branch 'master' of https://googleplex-android.googlesource.com/a/platform/frameworks/native

# Copyright 2012 The Android Open Source Project

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_SRC_FILES:= atrace.c

LOCAL_MODULE:= atrace

LOCAL_MODULE_TAGS:= optional

include $(BUILD_EXECUTABLE)

   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.

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/*

 * 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 <signal.h>

#include <stdarg.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <sys/sendfile.h>

#include <time.h>

/* Command line options */

static int g_traceDurationSeconds = 5;

static bool g_traceSchedSwitch = false;

static bool g_traceWorkqueue = false;

static bool g_traceOverwrite = false;

/* Global state */

static bool g_traceAborted = false;

/* Sys file paths */

static const char* k_traceClockPath =

    "/sys/kernel/debug/tracing/trace_clock";

static const char* k_tracingOverwriteEnablePath =

    "/sys/kernel/debug/tracing/options/overwrite";

static const char* k_schedSwitchEnablePath =

    "/sys/kernel/debug/tracing/events/sched/sched_switch/enable";

static const char* k_workqueueEnablePath =

    "/sys/kernel/debug/tracing/events/workqueue/enable";

static const char* k_tracingOnPath =

    "/sys/kernel/debug/tracing/tracing_on";

static const char* k_tracePath =

    "/sys/kernel/debug/tracing/trace";

static const char* k_traceMarkerPath =

    "/sys/kernel/debug/tracing/trace_marker";

// Write a string to a file, returning true if the write was successful.

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");

}

// 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 tracing of the kernel scheduler switching.

static bool setSchedSwitchTracingEnable(bool enable)

{

    return setKernelOptionEnable(k_schedSwitchEnablePath, enable);

}

// Enable or disable tracing of the kernel workqueues.

static bool setWorkqueueTracingEnabled(bool enable)

{

    return setKernelOptionEnable(k_workqueueEnablePath, 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;

}

// 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");

}

// Enable tracing in the kernel.

static bool startTrace()

{

    bool ok = true;

    // Set up the tracing options.

    ok &= setTraceOverwriteEnable(g_traceOverwrite);

    ok &= setSchedSwitchTracingEnable(g_traceSchedSwitch);

    ok &= setWorkqueueTracingEnabled(g_traceWorkqueue);

    ok &= setGlobalClockEnable(true);

    // Enable tracing.

    ok &= setTracingEnabled(true);

    if (!ok) {

        fprintf(stderr, "error: unable to start trace\n");

    }

    return ok;

}

// Disable tracing in the kernel.

static void stopTrace()

{

    // Disable tracing.

    setTracingEnabled(false);

    // Set the options back to their defaults.

    setTraceOverwriteEnable(true);

    setSchedSwitchTracingEnable(false);

    setWorkqueueTracingEnabled(false);

    setGlobalClockEnable(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;

    }

    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);

}

// Print the command usage help to stderr.

static void showHelp(const char *cmd)

{

    fprintf(stderr, "usage: %s [options]\n", cmd);

    fprintf(stderr, "options include:\n"

                    "  -c              trace into a circular buffer\n"

                    "  -s              trace the kernel scheduler switches\n"

                    "  -t N            trace for N seconds [defualt 5]\n"

                    "  -w              trace the kernel workqueue\n");

}

static void handleSignal(int signo) {

    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);

}

int main(int argc, char **argv)

{

    if (argc == 2 && 0 == strcmp(argv[1], "--help")) {

        showHelp(argv[0]);

        exit(0);

    }

    if (getuid() != 0) {

        fprintf(stderr, "error: %s must be run as root.", argv[0]);

    }

    for (;;) {

        int ret;

        ret = getopt(argc, argv, "cst:w");

        if (ret < 0) {

            break;

        }

        switch(ret) {

            case 'c':

                g_traceOverwrite = true;

            break;

            case 's':

                g_traceSchedSwitch = true;

            break;

            case 't':

                g_traceDurationSeconds = atoi(optarg);

            break;

            case 'w':

                g_traceWorkqueue = true;

            break;

            default:

                showHelp(argv[0]);

                exit(-1);

            break;

        }

    }

    registerSigHandler();

    bool ok = startTrace();

    if (ok) {

        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) {

            // 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.

    stopTrace();

    if (ok) {

        if (!g_traceAborted) {

            printf(" done\nTRACE:\n");

            fflush(stdout);

            dumpTrace();

        } else {

            printf("\ntrace aborted.\n");

            fflush(stdout);

        }

        clearTrace();

    } else {

        fprintf(stderr, "unable to start tracing\n");

    }

    return g_traceAborted ? 1 : 0;

}