1 /*
2  * Copyright (c) 2022 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef PMQOS_NETWORK_LATENCY_CONTROLLER_H
17 #define PMQOS_NETWORK_LATENCY_CONTROLLER_H
18 
19 #include <cerrno>
20 #include <cstddef>
21 #include <optional>
22 #include <string>
23 #include <string_view>
24 #include <utility>
25 
26 #include <fcntl.h>
27 #include <sys/types.h>
28 #include <sys/stat.h>
29 #include <unistd.h>
30 
31 #include <unique_fd.h>
32 
33 #include "inetwork_latency_switcher.h"
34 #include "res_sched_log.h"
35 
36 namespace OHOS::ResourceSchedule {
37 class PmqosNetworkLatencySwitcher : public INetworkLatencySwitcher {
38 public:
39     static inline std::string_view PMQOS_PATH = "/dev/network_latency";
40 
LowLatencyOn()41     virtual void LowLatencyOn() override
42     {
43         if (pmqosFd) {
44             RESSCHED_LOGE("%{public}s: fd is already opened", __func__);
45             return;
46         }
47 
48         UniqueFd fd(open(PMQOS_PATH.data(), O_WRONLY));
49         if (fd == -1) {
50             RESSCHED_LOGE("%{public}s: cannot open device file: %{public}d", __func__, errno);
51             return;
52         }
53 
54         ssize_t ret = write(fd, &PMQOS_LOW_LATENCY_VALUE, sizeof(PMQOS_LOW_LATENCY_VALUE));
55         if (ret == -1) {
56             RESSCHED_LOGE("%{public}s: cannot write to device: %{public}d", __func__, errno);
57             return;
58         }
59 
60         pmqosFd = std::move(fd);
61         RESSCHED_LOGD("%{public}s: pmqos activated", __func__);
62     }
63 
LowLatencyOff()64     virtual void LowLatencyOff() override
65     {
66         if (!pmqosFd) {
67             RESSCHED_LOGE("%{public}s: fd is already closed", __func__);
68             return;
69         }
70 
71         pmqosFd.reset();
72         RESSCHED_LOGD("%{public}s: pmqos deactivated", __func__);
73     }
74 private:
75     static inline int32_t PMQOS_LOW_LATENCY_VALUE = 0;
76     std::optional<UniqueFd> pmqosFd;
77 };
78 } // namespace OHOS::ResourceSchedule
79 
80 #endif // PMQOS_NETWORK_LATENCY_CONTROLLER_H
81