rusefi/firmware/development/perf_trace.cpp

139 lines
3.2 KiB
C++

/**
* @file perf_trace.cpp
*
* https://github.com/rusefi/rusefi/wiki/Developer-Performance-Tracing
*
* See JsonOutput.java in rusEfi console
*/
#include "pch.h"
#ifndef ENABLE_PERF_TRACE
#error ENABLE_PERF_TRACE must be defined!
#endif
enum class EPhase : char
{
Start,
End,
InstantThread,
InstantGlobal,
};
struct TraceEntry
{
PE Event;
EPhase Phase;
int8_t IsrId;
uint8_t ThreadId;
uint32_t Timestamp;
};
// Ensure that the struct is the size we think it is - the binary layout is important
static_assert(sizeof(TraceEntry) == 8);
#define TRACE_BUFFER_LENGTH (BIG_BUFFER_SIZE / sizeof(TraceEntry))
// This buffer stores a trace - we write the full buffer once, then disable tracing
static BigBufferHandle s_traceBuffer;
static size_t s_nextIdx = 0;
static bool s_isTracing = false;
static void stopTrace() {
s_isTracing = false;
s_nextIdx = 0;
}
static void perfEventImpl(PE event, EPhase phase) {
#if EFI_PROD_CODE
// Bail if we aren't allowed to trace
if constexpr (!ENABLE_PERF_TRACE) {
return;
}
// Bail if we aren't tracing
if (!s_isTracing || !s_traceBuffer) {
return;
}
// todo: why doesn't getTimeNowLowerNt() work here?
// It returns 0 like we're in a unit test
uint32_t timestamp = port_rt_get_counter_value();
size_t idx;
// Critical section: disable interrupts to reserve an index.
// We could lock, but this gets called a LOT - so locks could
// significantly alter the results of the measurement.
// In addition, if we want to trace lock/unlock events, we can't
// be locking ourselves from the trace functionality.
{
uint32_t prim = __get_PRIMASK();
__disable_irq();
idx = s_nextIdx++;
if (s_nextIdx >= TRACE_BUFFER_LENGTH) {
stopTrace();
}
// Restore previous interrupt state - don't restore if they weren't enabled
if (!prim) {
__enable_irq();
}
}
// We can safely write data out of the lock, our spot is reserved
volatile TraceEntry& entry = s_traceBuffer.get<TraceEntry>()[idx];
entry.Event = event;
entry.Phase = phase;
// Get the current active interrupt - this is the "process ID"
auto isr = static_cast<int8_t>(SCB->ICSR & SCB_ICSR_VECTACTIVE_Msk);
entry.IsrId = isr - 16;
// Get the current thread (if not interrupt) and use as the thread ID
if (isr == 0) {
entry.ThreadId = chThdGetSelfX()->threadId;
} else {
// Interrupts have no thread - all are T0
entry.ThreadId = 0;
}
entry.Timestamp = timestamp;
#endif // EFI_PROD_CODE
}
void perfEventBegin(PE event) {
perfEventImpl(event, EPhase::Start);
}
void perfEventEnd(PE event) {
perfEventImpl(event, EPhase::End);
}
void perfEventInstantGlobal(PE event) {
perfEventImpl(event, EPhase::InstantGlobal);
}
void perfTraceEnable() {
#if EFI_TOOTH_LOGGER
// force release of the buffer if occupied by the tooth logger
if (IsToothLoggerEnabled()) {
// don't worry, it will be automatically enabled
// when the next TS_GET_COMPOSITE_BUFFER_DONE_DIFFERENTLY command arrives
DisableToothLogger();
}
#endif // EFI_TOOTH_LOGGER
s_traceBuffer = getBigBuffer(BigBufferUser::PerfTrace);
s_isTracing = true;
}
const BigBufferHandle perfTraceGetBuffer() {
// stop tracing if you try to get the buffer early
stopTrace();
// transfer ownership of the buffer to the caller
return efi::move(s_traceBuffer);
}