1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specic language governing permissions and
14 * limitations under the License.
15 */
16
17 #define ATRACE_TAG (ATRACE_TAG_POWER | ATRACE_TAG_HAL)
18 #define LOG_TAG "libperfmgr"
19
20 #include "perfmgr/FileNode.h"
21
22 #include <android-base/chrono_utils.h>
23 #include <android-base/file.h>
24 #include <android-base/logging.h>
25 #include <android-base/properties.h>
26 #include <android-base/stringprintf.h>
27 #include <android-base/strings.h>
28 #include <utils/Trace.h>
29
30 namespace android {
31 namespace perfmgr {
32
FileNode(std::string name,std::string node_path,std::vector<RequestGroup> req_sorted,std::size_t default_val_index,bool reset_on_init,bool truncate,bool hold_fd,bool write_only)33 FileNode::FileNode(std::string name, std::string node_path, std::vector<RequestGroup> req_sorted,
34 std::size_t default_val_index, bool reset_on_init, bool truncate, bool hold_fd,
35 bool write_only)
36 : Node(std::move(name), std::move(node_path), std::move(req_sorted), default_val_index,
37 reset_on_init),
38 hold_fd_(hold_fd),
39 truncate_(truncate),
40 write_only_(write_only),
41 warn_timeout_(android::base::GetBoolProperty("ro.debuggable", false) ? 5ms : 50ms) {}
42
Update(bool log_error)43 std::chrono::milliseconds FileNode::Update(bool log_error) {
44 std::size_t value_index = default_val_index_;
45 std::chrono::milliseconds expire_time = std::chrono::milliseconds::max();
46
47 // Find the highest outstanding request's expire time
48 for (std::size_t i = 0; i < req_sorted_.size(); i++) {
49 if (req_sorted_[i].GetExpireTime(&expire_time)) {
50 value_index = i;
51 break;
52 }
53 }
54
55 // Update node only if request index changes
56 if (value_index != current_val_index_ || reset_on_init_) {
57 const std::string& req_value =
58 req_sorted_[value_index].GetRequestValue();
59 if (ATRACE_ENABLED()) {
60 ATRACE_INT(("N:" + GetName()).c_str(), value_index);
61 const std::string tag =
62 GetName() + ":" + req_value + ":" + std::to_string(expire_time.count());
63 ATRACE_BEGIN(tag.c_str());
64 }
65 android::base::Timer t;
66 int flags = O_WRONLY | O_CLOEXEC;
67 if (GetTruncate()) {
68 flags |= O_TRUNC;
69 }
70 fd_.reset(TEMP_FAILURE_RETRY(open(node_path_.c_str(), flags)));
71
72 if (fd_ == -1 || !android::base::WriteStringToFd(req_value, fd_)) {
73 if (log_error) {
74 LOG(WARNING) << "Failed to write to node: " << node_path_
75 << " with value: " << req_value << ", fd: " << fd_;
76 }
77 // Retry in 500ms or sooner
78 expire_time = std::min(expire_time, std::chrono::milliseconds(500));
79 } else {
80 // For regular file system, we need fsync
81 fsync(fd_);
82 // Some dev node requires file to remain open during the entire hint
83 // duration e.g. /dev/cpu_dma_latency, so fd_ is intentionally kept
84 // open during any requested value other than default one. If
85 // request a default value, node will write the value and then
86 // release the fd.
87 if ((!hold_fd_) || value_index == default_val_index_) {
88 fd_.reset();
89 }
90 auto duration = t.duration();
91 if (duration > warn_timeout_) {
92 LOG(WARNING) << "Slow writing to file: '" << node_path_
93 << "' with value: '" << req_value
94 << "' took: " << duration.count() << " ms";
95 }
96 // Update current index only when succeed
97 current_val_index_ = value_index;
98 reset_on_init_ = false;
99 }
100 if (ATRACE_ENABLED()) {
101 ATRACE_END();
102 }
103 }
104 return expire_time;
105 }
106
GetHoldFd() const107 bool FileNode::GetHoldFd() const {
108 return hold_fd_;
109 }
110
GetTruncate() const111 bool FileNode::GetTruncate() const {
112 return truncate_;
113 }
114
DumpToFd(int fd) const115 void FileNode::DumpToFd(int fd) const {
116 std::string node_value;
117 if (!write_only_ && !android::base::ReadFileToString(node_path_, &node_value)) {
118 LOG(ERROR) << "Failed to read node path: " << node_path_;
119 }
120 node_value = android::base::Trim(node_value);
121 std::string buf(
122 android::base::StringPrintf("Node Name\t"
123 "Node Path\t"
124 "Current Index\t"
125 "Current Value\t"
126 "Hold FD\t"
127 "Truncate\n"
128 "%s\t%s\t%zu\t%s\t%d\t%d\n",
129 name_.c_str(), node_path_.c_str(), current_val_index_,
130 node_value.c_str(), hold_fd_, truncate_));
131 if (!android::base::WriteStringToFd(buf, fd)) {
132 LOG(ERROR) << "Failed to dump fd: " << fd;
133 }
134 for (std::size_t i = 0; i < req_sorted_.size(); i++) {
135 req_sorted_[i].DumpToFd(
136 fd, android::base::StringPrintf("\t\tReq%zu:\t", i));
137 }
138 }
139
140 } // namespace perfmgr
141 } // namespace android
142