| /* |
| * Copyright (C) 2019 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. |
| */ |
| |
| #ifndef SRC_TRACE_PROCESSOR_TYPES_TASK_STATE_H_ |
| #define SRC_TRACE_PROCESSOR_TYPES_TASK_STATE_H_ |
| |
| #include <stdint.h> |
| #include <array> |
| #include <optional> |
| |
| #include "src/trace_processor/types/version_number.h" |
| |
| namespace perfetto { |
| namespace trace_processor { |
| namespace ftrace_utils { |
| |
| // Linux kernel scheduling events (sched_switch) contain a bitmask of the |
| // switched-out task's state (prev_state). Perfetto doesn't record the event |
| // format string during tracing, the trace contains only the raw bitmask as an |
| // integer. Certain kernel versions made backwards incompatible changes to the |
| // bitmask's raw representation, so this class guesses how to decode the flags |
| // based on the kernel's major+minor version as recorded in the trace. Note: |
| // this means we can be wrong if patch backports change the flags, or the |
| // kernel diverged from upstream. But this has worked well enough in practice |
| // so far. |
| // |
| // There are three specific kernel version intervals we handle: |
| // * [4.14, ...) |
| // * [4.8, 4.14) |
| // * (..., 4.8), where we assume the 4.4 bitmask |
| // |
| // (Therefore kernels before 4.2 most likely have incorrect preemption flag |
| // parsing.) |
| // |
| // For 4.14, we assume that the kernel has a backport of the bugfix |
| // https://github.com/torvalds/linux/commit/3f5fe9fe ("sched/debug: Fix task |
| // state recording/printout"). In other words, traces collected on unpatched |
| // 4.14 kernels will have incorrect flags decoded. |
| class TaskState { |
| public: |
| using TaskStateStr = std::array<char, 4>; |
| |
| // We transcode the raw bitmasks into a set of these flags to make them |
| // kernel version agnostic. |
| // |
| // Warning: do NOT depend on the numeric values of these constants, and |
| // especially do NOT attempt to use these constants when operating on raw |
| // prev_state masks unless you're changing task_state.cc itself. |
| enum ParsedFlag : uint16_t { |
| kRunnable = 0x0000, // no flag (besides kPreempted) means "running" |
| kInterruptibleSleep = 0x0001, |
| kUninterruptibleSleep = 0x0002, |
| kStopped = 0x0004, |
| kTraced = 0x0008, |
| kExitDead = 0x0010, |
| kExitZombie = 0x0020, |
| |
| // Starting from here, different kernels have different values: |
| kParked = 0x0040, |
| |
| // No longer reported on 4.14+: |
| kTaskDead = 0x0080, |
| kWakeKill = 0x0100, |
| kWaking = 0x0200, |
| kNoLoad = 0x0400, |
| |
| // Special states that don't map onto the scheduler's constants: |
| kIdle = 0x4000, |
| kPreempted = 0x8000, // exclusive as only running tasks can be preempted |
| |
| // Sentinel value that is an invalid combination of flags: |
| kInvalid = 0xffff |
| }; |
| |
| static TaskState FromRawPrevState( |
| uint16_t raw_state, |
| std::optional<VersionNumber> kernel_version); |
| static TaskState FromSystrace(const char* state_str); |
| static TaskState FromParsedFlags(uint16_t parsed_state); |
| |
| // TODO(rsavitski): consider moving the factory methods to an optional return |
| // type instead. |
| bool is_valid() const { return parsed_ != kInvalid; } |
| |
| // Returns the textual representation of this state as a null-terminated |
| // array. |separator| specifies if a separator should be printed between the |
| // atoms (default: \0 meaning no separator). |
| TaskStateStr ToString(char separator = '\0') const; |
| |
| // Converts the TaskState back to the raw format, to be used only when |
| // parsing systrace. |
| // NB: this makes a hard assumption on the 4.4 flag layout, since systrace |
| // files don't specify a kernel version, so when trace_processor later calls |
| // FromRawPrevState to construct sched.end_state column values, it'll default |
| // to the 4.4 layout. |
| // TODO(rsavitski): can we get rid of this entirely and avoid the |
| // str -> TaskState -> uint16_t -> str conversion chain? |
| uint16_t ToRawStateOnlyForSystraceConversions() const; |
| |
| uint16_t ParsedForTesting() const { return parsed_; } |
| |
| private: |
| TaskState() = default; |
| explicit TaskState(uint16_t raw_state, |
| std::optional<VersionNumber> kernel_version); |
| explicit TaskState(const char* state_str); |
| |
| bool is_runnable() const { return !(parsed_ & ~kPreempted); } |
| |
| uint16_t parsed_ = 0; |
| }; |
| |
| } // namespace ftrace_utils |
| } // namespace trace_processor |
| } // namespace perfetto |
| |
| #endif // SRC_TRACE_PROCESSOR_TYPES_TASK_STATE_H_ |