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//===-- PerfContextSwitchDecoder.h --======----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_PERFCONTEXTSWITCHDECODER_H
#define LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_PERFCONTEXTSWITCHDECODER_H
#include "lldb/Utility/TraceIntelPTGDBRemotePackets.h"
#include "lldb/lldb-types.h"
#include "llvm/Support/Error.h"
#include <set>
#include <vector>
namespace lldb_private {
namespace trace_intel_pt {
/// This class indicates the time interval in which a thread was running
/// continuously on a cpu core.
struct ThreadContinuousExecution {
/// In most cases both the start and end of a continuous execution can be
/// accurately recovered from the context switch trace, but in some cases one
/// of these endpoints might be guessed or not known at all, due to contention
/// problems in the trace or because tracing was interrupted, e.g. with ioctl
/// calls, which causes gaps in the trace. Because of that, we identify which
/// situation we fall into with the following variants.
enum class Variant {
/// Both endpoints are known.
Complete,
/// The end is known and we have a lower bound for the start, i.e. the
/// previous execution in the same cpu happens strictly before the hinted
/// start.
HintedStart,
/// The start is known and we have an upper bound for the end, i.e. the next
/// execution in the same cpu happens strictly after the hinted end.
HintedEnd,
/// We only know the start. This might be the last entry of a cpu trace.
OnlyStart,
/// We only know the end. This might be the first entry or a cpu trace.
OnlyEnd,
} variant;
/// \return
/// The lowest tsc that we are sure of, i.e. not hinted.
uint64_t GetLowestKnownTSC() const;
/// \return
/// The known or hinted start tsc, or 0 if the variant is \a OnlyEnd.
uint64_t GetStartTSC() const;
/// \return
/// The known or hinted end tsc, or max \a uint64_t if the variant is \a
/// OnlyStart.
uint64_t GetEndTSC() const;
/// Constructors for the different variants of this object
///
/// \{
static ThreadContinuousExecution
CreateCompleteExecution(lldb::cpu_id_t cpu_id, lldb::tid_t tid,
lldb::pid_t pid, uint64_t start, uint64_t end);
static ThreadContinuousExecution
CreateHintedStartExecution(lldb::cpu_id_t cpu_id, lldb::tid_t tid,
lldb::pid_t pid, uint64_t hinted_start,
uint64_t end);
static ThreadContinuousExecution
CreateHintedEndExecution(lldb::cpu_id_t cpu_id, lldb::tid_t tid,
lldb::pid_t pid, uint64_t start,
uint64_t hinted_end);
static ThreadContinuousExecution CreateOnlyEndExecution(lldb::cpu_id_t cpu_id,
lldb::tid_t tid,
lldb::pid_t pid,
uint64_t end);
static ThreadContinuousExecution
CreateOnlyStartExecution(lldb::cpu_id_t cpu_id, lldb::tid_t tid,
lldb::pid_t pid, uint64_t start);
/// \}
union {
struct {
uint64_t start;
uint64_t end;
} complete;
struct {
uint64_t start;
} only_start;
struct {
uint64_t end;
} only_end;
/// The following 'hinted' structures are useful when there are contention
/// problems in the trace
struct {
uint64_t hinted_start;
uint64_t end;
} hinted_start;
struct {
uint64_t start;
uint64_t hinted_end;
} hinted_end;
} tscs;
lldb::cpu_id_t cpu_id;
lldb::tid_t tid;
lldb::pid_t pid;
private:
/// We keep this constructor private to force the usage of the static named
/// constructors.
ThreadContinuousExecution(lldb::cpu_id_t cpu_id, lldb::tid_t tid,
lldb::pid_t pid)
: cpu_id(cpu_id), tid(tid), pid(pid) {}
};
/// Decodes a context switch trace collected with perf_event_open.
///
/// \param[in] data
/// The context switch trace in binary format.
///
/// \param[i] cpu_id
/// The cpu_id where the trace were gotten from.
///
/// \param[in] tsc_conversion
/// The conversion values used to confert nanoseconds to TSC.
///
/// \return
/// A list of continuous executions recovered from the raw trace sorted by
/// time, or an \a llvm::Error if the data is malformed.
llvm::Expected<std::vector<ThreadContinuousExecution>>
DecodePerfContextSwitchTrace(llvm::ArrayRef<uint8_t> data,
lldb::cpu_id_t cpu_id,
const LinuxPerfZeroTscConversion &tsc_conversion);
llvm::Expected<std::vector<uint8_t>>
FilterProcessesFromContextSwitchTrace(llvm::ArrayRef<uint8_t> data,
const std::set<lldb::pid_t> &pids);
} // namespace trace_intel_pt
} // namespace lldb_private
#endif // LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_PERFCONTEXTSWITCHDECODER_H
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