Files
filament/libs/utils/src/Systrace.cpp
2018-08-03 10:38:22 -07:00

141 lines
4.9 KiB
C++

/*
* 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 <utils/Systrace.h>
#if defined(ANDROID)
#include <cinttypes>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
namespace utils {
namespace details {
/**
* 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 512
std::atomic_bool Systrace::sIsTracingReady = { false };
std::atomic<uint32_t> Systrace::sIsTracingEnabled = { 0 };
bool Systrace::sIsTracingAvailable = false;
int Systrace::sMarkerFd = -1;
static pthread_once_t atrace_once_control = PTHREAD_ONCE_INIT;
void Systrace::init_once() noexcept {
sMarkerFd = open("/sys/kernel/debug/tracing/trace_marker", O_WRONLY | O_CLOEXEC);
if (UTILS_UNLIKELY(sMarkerFd == -1)) {
fprintf(stderr, "Error opening trace file: %s (%d)", strerror(errno), errno);
} else {
sIsTracingAvailable = true;
}
std::atomic_store_explicit(&sIsTracingReady, true, std::memory_order_release);
}
void Systrace::setup() noexcept {
pthread_once(&atrace_once_control, init_once);
}
void Systrace::enable(uint32_t tags) noexcept {
init();
if (UTILS_LIKELY(sIsTracingAvailable)) {
sIsTracingEnabled.fetch_or(tags, std::memory_order_relaxed);
}
}
void Systrace::disable(uint32_t tags) noexcept {
sIsTracingEnabled.fetch_and(~tags, std::memory_order_relaxed);
}
// unfortunately, this generates quite a bit of code because reading a global is not
// trivial. For this reason, we do not inline this method.
bool Systrace::isTracingEnabled(uint32_t tag) noexcept {
if (tag) {
init();
return bool((sIsTracingEnabled.load(std::memory_order_relaxed) | SYSTRACE_TAG_ALWAYS) & tag);
}
return false;
}
// ------------------------------------------------------------------------------------------------
void Systrace::begin_body(int fd, int pid, const char* name) noexcept {
char buf[ATRACE_MESSAGE_LENGTH];
ssize_t len = snprintf(buf, sizeof(buf), "B|%d|%s", pid, name);
if (len >= sizeof(buf)) {
len = sizeof(buf) - 1;
}
write(fd, buf, size_t(len));
}
#define WRITE_MSG(format_begin, format_end, pid, name, value) { \
char buf[ATRACE_MESSAGE_LENGTH]; \
int len = snprintf(buf, sizeof(buf), format_begin "%s" format_end, pid, \
name, value); \
if (len >= (int) sizeof(buf)) { \
/* Given the sizeof(buf), and all of the current format buffers, \
* it is impossible for name_len to be < 0 if len >= sizeof(buf). */ \
int name_len = strlen(name) - (len - sizeof(buf)) - 1; \
/* Truncate the name to make the message fit. */ \
fprintf(stderr, "Truncated name in %s: %s\n", __FUNCTION__, name); \
len = snprintf(buf, sizeof(buf), format_begin "%.*s" format_end, pid, \
name_len, name, value); \
} \
write(fd, buf, len); \
}
void Systrace::async_begin_body(int fd, int pid, const char* name, int32_t cookie) noexcept {
WRITE_MSG("S|%d|", "|%" PRId32, pid, name, cookie);
}
void Systrace::async_end_body(int fd, int pid, const char* name, int32_t cookie) noexcept {
WRITE_MSG("F|%d|", "|%" PRId32, pid, name, cookie);
}
void Systrace::int_body(int fd, int pid, const char* name, int32_t value) noexcept {
WRITE_MSG("C|%d|", "|%" PRId32, pid, name, value);
}
void Systrace::int64_body(int fd, int pid, const char* name, int64_t value) noexcept {
WRITE_MSG("C|%d|", "|%" PRId64, pid, name, value);
}
// ------------------------------------------------------------------------------------------------
void Systrace::init(uint32_t tag) noexcept {
// must be called first
mIsTracingEnabled = isTracingEnabled(tag);
// these are now initialized
mMarkerFd = sMarkerFd;
mPid = getpid();
}
} // namespace details
} // namespace utils
#endif // ANDROID