| // Copyright 2017 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef CHROMECAST_TRACING_FTRACE_H_ |
| #define CHROMECAST_TRACING_FTRACE_H_ |
| |
| #include <string> |
| #include <vector> |
| |
| #include "base/files/scoped_file.h" |
| #include "base/strings/string_piece.h" |
| |
| namespace chromecast { |
| namespace tracing { |
| |
| // Returns true if |category| is valid for system tracing. |
| bool IsValidCategory(base::StringPiece category); |
| |
| // Starts ftrace for the specified categories. |
| // |
| // This must be paired with StopFtrace() or the kernel will continue tracing |
| // indefinitely. Returns false if an error occurs writing to tracefs - this |
| // usually indicates a configuration issue (e.g. tracefs not mounted). |
| bool StartFtrace(const std::vector<std::string>& categories); |
| |
| // Writes time synchronization marker. |
| // |
| // This is used by trace-viewer to align ftrace clock with userspace |
| // tracing. Since CLOCK_MONOTONIC is used in both cases, this merely |
| // writes a zero offset. Call it at the end of tracing right before |
| // StopFtrace(). Returns false if an error occurs writing to tracefs. |
| bool WriteFtraceTimeSyncMarker(); |
| |
| // Stops ftrace. |
| // |
| // This is safe to call even if tracing isn't started. Returns false if an error |
| // occurs writing to tracefs. |
| bool StopFtrace(); |
| |
| // Opens ftrace buffer for reading. |
| base::ScopedFD GetFtraceData(); |
| |
| // Clears ftrace buffer. Returns false if an error occurs writing to tracefs. |
| bool ClearFtrace(); |
| |
| } // namespace tracing |
| } // namespace chromecast |
| |
| #endif // CHROMECAST_TRACING_FTRACE_H_ |