Merge "cutils: Add tracing support"

include/cutils/trace.h

@@ -0,0 +1,192 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBS_CUTILS_TRACE_H
+#define _LIBS_CUTILS_TRACE_H
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <cutils/atomic.h>
+#include <cutils/compiler.h>
+
+__BEGIN_DECLS
+
+/**
+ * The ATRACE_TAG macro can be defined before including this header to trace
+ * using one of the tags defined below.  It must be defined to one of the
+ * following ATRACE_TAG_* macros.  The trace tag is used to filter tracing in
+ * userland to avoid some of the runtime cost of tracing when it is not desired.
+ *
+ * Defining ATRACE_TAG to be ATRACE_TAG_ALWAYS will result in the tracing always
+ * being enabled - this should ONLY be done for debug code, as userland tracing
+ * has a performance cost even when the trace is not being recorded.  Defining
+ * ATRACE_TAG to be ATRACE_TAG_NEVER or leaving ATRACE_TAG undefined will result
+ * in the tracing always being disabled.
+ *
+ * ATRACE_TAG_HAL should be bitwise ORed with the relevant tags for tracing
+ * within a hardware module.  For example a camera hardware module would set:
+ * #define ATRACE_TAG  (ATRACE_TAG_CAMERA | ATRACE_TAG_HAL)
+ *
+ * Keep these in sync with frameworks/base/core/java/android/os/Trace.java.
+ */
+#define ATRACE_TAG_NEVER            0       // This tag is never enabled.
+#define ATRACE_TAG_ALWAYS           (1<<0)  // This tag is always enabled.
+#define ATRACE_TAG_GRAPHICS         (1<<1)
+#define ATRACE_TAG_INPUT            (1<<2)
+#define ATRACE_TAG_VIEW             (1<<3)
+#define ATRACE_TAG_WEBVIEW          (1<<4)
+#define ATRACE_TAG_WINDOW_MANAGER   (1<<5)
+#define ATRACE_TAG_ACTIVITY_MANAGER (1<<6)
+#define ATRACE_TAG_SYNC_MANAGER     (1<<7)
+#define ATRACE_TAG_AUDIO            (1<<8)
+#define ATRACE_TAG_VIDEO            (1<<9)
+#define ATRACE_TAG_CAMERA           (1<<10)
+#define ATRACE_TAG_HAL              (1<<11)
+#define ATRACE_TAG_LAST             ATRACE_TAG_HAL
+
+// Reserved for initialization.
+#define ATRACE_TAG_NOT_READY        (1LL<<63)
+
+#define ATRACE_TAG_VALID_MASK ((ATRACE_TAG_LAST - 1) | ATRACE_TAG_LAST)
+
+#ifndef ATRACE_TAG
+#define ATRACE_TAG ATRACE_TAG_NEVER
+#elif ATRACE_TAG > ATRACE_TAG_VALID_MASK
+#error ATRACE_TAG must be defined to be one of the tags defined in cutils/trace.h
+#endif
+
+/**
+ * Maximum size of a message that can be logged to the trace buffer.
+ * Note this message includes a tag, the pid, and the string given as the name.
+ * Names should be kept short to get the most use of the trace buffer.
+ */
+#define ATRACE_MESSAGE_LENGTH 1024
+
+/**
+ * Opens the trace file for writing and reads the property for initial tags.
+ * The atrace.tags.enableflags property sets the tags to trace.
+ * This function should not be explicitly called, the first call to any normal
+ * trace function will cause it to be run safely.
+ */
+void atrace_setup();
+
+/**
+ * Flag indicating whether setup has been completed, initialized to 0.
+ * Nonzero indicates setup has completed.
+ * Note: This does NOT indicate whether or not setup was successful.
+ */
+extern int32_t atrace_is_ready;
+
+/**
+ * Set of ATRACE_TAG flags to trace for, initialized to ATRACE_TAG_NOT_READY.
+ * A value of zero indicates setup has failed.
+ * Any other nonzero value indicates setup has succeeded, and tracing is on.
+ */
+extern uint64_t atrace_enabled_tags;
+
+/**
+ * Handle to the kernel's trace buffer, initialized to -1.
+ * Any other value indicates setup has succeeded, and is a valid fd for tracing.
+ */
+extern int atrace_marker_fd;
+
+/**
+ * atrace_init readies the process for tracing by opening the trace_marker file.
+ * Calling any trace function causes this to be run, so calling it is optional.
+ * This can be explicitly run to avoid setup delay on first trace function.
+ */
+#define ATRACE_INIT() atrace_init()
+static inline void atrace_init()
+{
+    if (CC_UNLIKELY(!android_atomic_acquire_load(&atrace_is_ready))) {
+        atrace_setup();
+    }
+}
+
+/**
+ * Get the mask of all tags currently enabled.
+ * It can be used as a guard condition around more expensive trace calculations.
+ * Every trace function calls this, which ensures atrace_init is run.
+ */
+#define ATRACE_GET_ENABLED_TAGS() atrace_get_enabled_tags()
+static inline uint64_t atrace_get_enabled_tags()
+{
+    atrace_init();
+    return atrace_enabled_tags;
+}
+
+/**
+ * Test if a given tag is currently enabled.
+ * Returns nonzero if the tag is enabled, otherwise zero.
+ * It can be used as a guard condition around more expensive trace calculations.
+ */
+#define ATRACE_ENABLED() atrace_is_tag_enabled(ATRACE_TAG)
+static inline uint64_t atrace_is_tag_enabled(uint64_t tag)
+{
+    return atrace_get_enabled_tags() & tag;
+}
+
+/**
+ * Trace the beginning of a context.  name is used to identify the context.
+ * This is often used to time function execution.
+ */
+#define ATRACE_BEGIN(name) atrace_begin(ATRACE_TAG, name)
+static inline void atrace_begin(uint64_t tag, const char* name)
+{
+    if (CC_UNLIKELY(atrace_is_tag_enabled(tag))) {
+        char buf[ATRACE_MESSAGE_LENGTH];
+        size_t len;
+
+        len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "B|%d|%s", getpid(), name);
+        write(atrace_marker_fd, buf, len);
+    }
+}
+
+/**
+ * Trace the end of a context.
+ * This should match up (and occur after) a corresponding ATRACE_BEGIN.
+ */
+#define ATRACE_END() atrace_end(ATRACE_TAG)
+static inline void atrace_end(uint64_t tag)
+{
+    if (CC_UNLIKELY(atrace_is_tag_enabled(tag))) {
+        char c = 'E';
+        write(atrace_marker_fd, &c, 1);
+    }
+}
+
+/**
+ * Traces an integer counter value.  name is used to identify the counter.
+ * This can be used to track how a value changes over time.
+ */
+#define ATRACE_INT(name, value) atrace_int(ATRACE_TAG, name, value)
+static inline void atrace_int(uint64_t tag, const char* name, int32_t value)
+{
+    if (CC_UNLIKELY(atrace_is_tag_enabled(tag))) {
+        char buf[ATRACE_MESSAGE_LENGTH];
+        size_t len;
+
+        len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "C|%d|%s|%d",
+                getpid(), name, value);
+        write(atrace_marker_fd, buf, len);
+    }
+}
+
+__END_DECLS
+
+#endif // _LIBS_CUTILS_TRACE_H

libcutils/Android.mk

@@ -121,6 +121,7 @@ LOCAL_SRC_FILES := $(commonSources) \
         mq.c \
         partition_utils.c \
         qtaguid.c \
+        trace.c \
         uevent.c
 
 ifeq ($(TARGET_ARCH),arm)

libcutils/trace.c

@@ -0,0 +1,75 @@
+/*
+ * 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 <limits.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <cutils/atomic.h>
+#include <cutils/compiler.h>
+#include <cutils/properties.h>
+#include <cutils/trace.h>
+
+#define LOG_TAG "cutils-trace"
+#include <cutils/log.h>
+
+int32_t               atrace_is_ready     = 0;
+int                   atrace_marker_fd    = -1;
+uint64_t              atrace_enabled_tags = ATRACE_TAG_NOT_READY;
+static pthread_once_t atrace_once_control = PTHREAD_ONCE_INIT;
+
+// Read the sysprop and return the value tags should be set to
+static uint64_t atrace_get_property()
+{
+    char value[PROPERTY_VALUE_MAX];
+    char *endptr;
+    uint64_t tags;
+
+    property_get("debug.atrace.tags.enableflags", value, "0");
+    errno = 0;
+    tags = strtoull(value, &endptr, 0);
+    if (value[0] == '\0' || *endptr != '\0') {
+        ALOGE("Error parsing trace property: Not a number: %s", value);
+        return 0;
+    } else if (errno == ERANGE || tags == ULLONG_MAX) {
+        ALOGE("Error parsing trace property: Number too large: %s", value);
+        return 0;
+    }
+    return (tags | ATRACE_TAG_ALWAYS) & ATRACE_TAG_VALID_MASK;
+}
+
+static void atrace_init_once()
+{
+    atrace_marker_fd = open("/sys/kernel/debug/tracing/trace_marker", O_WRONLY);
+    if (atrace_marker_fd == -1) {
+        ALOGE("Error opening trace file: %s (%d)", strerror(errno), errno);
+        atrace_enabled_tags = 0;
+        goto done;
+    }
+
+    atrace_enabled_tags = atrace_get_property();
+
+done:
+    android_atomic_release_store(1, &atrace_is_ready);
+}
+
+void atrace_setup()
+{
+    pthread_once(&atrace_once_control, atrace_init_once);
+}