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/*
* Copyright (C) 2017 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 specic language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "libperfmgr"
#include "perfmgr/FileNode.h"
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
namespace android {
namespace perfmgr {
FileNode::FileNode(std::string name, std::string node_path,
std::vector<RequestGroup> req_sorted,
std::size_t default_val_index, bool reset_on_init,
bool hold_fd)
: Node(std::move(name), std::move(node_path), std::move(req_sorted),
default_val_index, reset_on_init),
hold_fd_(hold_fd),
warn_timeout_(
android::base::GetBoolProperty("ro.debuggable", false) ? 5ms : 50ms) {
}
std::chrono::milliseconds FileNode::Update(bool log_error) {
std::size_t value_index = default_val_index_;
std::chrono::milliseconds expire_time = std::chrono::milliseconds::max();
// Find the highest outstanding request's expire time
for (std::size_t i = 0; i < req_sorted_.size(); i++) {
if (req_sorted_[i].GetExpireTime(&expire_time)) {
value_index = i;
break;
}
}
// Update node only if request index changes
if (value_index != current_val_index_ || reset_on_init_) {
const std::string& req_value =
req_sorted_[value_index].GetRequestValue();
android::base::Timer t;
fd_.reset(TEMP_FAILURE_RETRY(
open(node_path_.c_str(), O_WRONLY | O_CLOEXEC | O_TRUNC)));
if (fd_ == -1 || !android::base::WriteStringToFd(req_value, fd_)) {
if (log_error) {
LOG(WARNING) << "Failed to write to node: " << node_path_
<< " with value: " << req_value << ", fd: " << fd_;
}
// Retry in 500ms or sooner
expire_time = std::min(expire_time, std::chrono::milliseconds(500));
} else {
// For regular file system, we need fsync
fsync(fd_);
// Some dev node requires file to remain open during the entire hint
// duration e.g. /dev/cpu_dma_latency, so fd_ is intentionally kept
// open during any requested value other than default one. If
// request a default value, node will write the value and then
// release the fd.
if ((!hold_fd_) || value_index == default_val_index_) {
fd_.reset();
}
auto duration = t.duration();
if (duration > warn_timeout_) {
LOG(WARNING) << "Slow writing to file: '" << node_path_
<< "' with value: '" << req_value
<< "' took: " << duration.count() << " ms";
}
// Update current index only when succeed
current_val_index_ = value_index;
reset_on_init_ = false;
}
}
return expire_time;
}
bool FileNode::GetHoldFd() const {
return hold_fd_;
}
void FileNode::DumpToFd(int fd) const {
std::string node_value;
if (!android::base::ReadFileToString(node_path_, &node_value)) {
LOG(ERROR) << "Failed to read node path: " << node_path_;
}
node_value = android::base::Trim(node_value);
std::string buf(android::base::StringPrintf(
"%s\t%s\t%zu\t%s\n", name_.c_str(), node_path_.c_str(),
current_val_index_, node_value.c_str()));
if (!android::base::WriteStringToFd(buf, fd)) {
LOG(ERROR) << "Failed to dump fd: " << fd;
}
for (std::size_t i = 0; i < req_sorted_.size(); i++) {
req_sorted_[i].DumpToFd(
fd, android::base::StringPrintf("\t\tReq%zu:\t", i));
}
}
} // namespace perfmgr
} // namespace android
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