Add a tool for setting uclamp for given PID

Test: run
Bug: 205764497
Change-Id: I5afb92909a93728909dd43b6aa92d36f0d965630

2 files changed, 102 insertions, 0 deletions

diff --git a/setuclamp/Android.bp b/setuclamp/Android.bp
new file mode 100644
index 00000000..4980aea2
--- /dev/null
+++ b/setuclamp/Android.bp
@@ -0,0 +1,27 @@
+// Copyright (C) 2021 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.
+
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_binary {
+    name: "setuclamp",
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+
+    srcs: ["setuclamp.cpp"],
+}
diff --git a/setuclamp/setuclamp.cpp b/setuclamp/setuclamp.cpp
new file mode 100644
index 00000000..e40fb0fd
--- /dev/null
+++ b/setuclamp/setuclamp.cpp
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2021 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 <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <iostream>
+
+[[noreturn]] static void usage(int exit_status) {
+    std::cerr << "Usage: " << getprogname() << " <tid> <uclamp_min> <uclamp_max>" << std::endl
+              << "    tid      Thread ID to apply the uclamp setting." << std::endl
+              << "    uclamp_min  uclamp.min value range from [0, 1024]." << std::endl
+              << "    uclamp_max  uclamp.max value range from [0, 1024]." << std::endl;
+    exit(exit_status);
+}
+
+struct sched_attr {
+    __u32 size;
+    __u32 sched_policy;
+    __u64 sched_flags;
+    __s32 sched_nice;
+    __u32 sched_priority;
+    __u64 sched_runtime;
+    __u64 sched_deadline;
+    __u64 sched_period;
+    __u32 sched_util_min;
+    __u32 sched_util_max;
+};
+
+static int sched_setattr(int pid, struct sched_attr* attr, unsigned int flags) {
+    return syscall(__NR_sched_setattr, pid, attr, flags);
+}
+
+static int set_uclamp(int32_t min, int32_t max, int tid) {
+    sched_attr attr = {};
+    attr.size = sizeof(attr);
+
+    attr.sched_flags = (SCHED_FLAG_KEEP_ALL | SCHED_FLAG_UTIL_CLAMP);
+    attr.sched_util_min = min;
+    attr.sched_util_max = max;
+
+    int ret = sched_setattr(tid, &attr, 0);
+    if (ret) {
+        int err = errno;
+        std::cerr << "sched_setattr failed for thread " << tid << " err=" << err << std::endl;
+    }
+
+    return ret;
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 4) {
+        usage(EXIT_FAILURE);
+    }
+
+    int tid = atoi(argv[1]);
+    int uclamp_min = atoi(argv[2]);
+    int uclamp_max = atoi(argv[3]);
+
+    return set_uclamp(uclamp_min, uclamp_max, tid);
+}