blob: a7e1382c3865bd1444ae8fedb5f31826e21ace21 [file] [log] [blame]
//===-- xray_fdr_logging.cc ------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of XRay, a dynamic runtime instrumentation system.
//
// Here we implement the Flight Data Recorder mode for XRay, where we use
// compact structures to store records in memory as well as when writing out the
// data to files.
//
//===----------------------------------------------------------------------===//
#include "xray_fdr_logging.h"
#include <algorithm>
#include <bitset>
#include <cerrno>
#include <cstring>
#include <sys/syscall.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include <unordered_map>
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_common.h"
#include "xray/xray_interface.h"
#include "xray/xray_records.h"
#include "xray_buffer_queue.h"
#include "xray_defs.h"
#include "xray_fdr_logging_impl.h"
#include "xray_flags.h"
#include "xray_tsc.h"
#include "xray_utils.h"
namespace __xray {
// Global BufferQueue.
std::shared_ptr<BufferQueue> BQ;
__sanitizer::atomic_sint32_t LogFlushStatus = {
XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING};
FDRLoggingOptions FDROptions;
__sanitizer::SpinMutex FDROptionsMutex;
// Must finalize before flushing.
XRayLogFlushStatus fdrLoggingFlush() XRAY_NEVER_INSTRUMENT {
if (__sanitizer::atomic_load(&LoggingStatus,
__sanitizer::memory_order_acquire) !=
XRayLogInitStatus::XRAY_LOG_FINALIZED)
return XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING;
s32 Result = XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING;
if (!__sanitizer::atomic_compare_exchange_strong(
&LogFlushStatus, &Result, XRayLogFlushStatus::XRAY_LOG_FLUSHING,
__sanitizer::memory_order_release))
return static_cast<XRayLogFlushStatus>(Result);
// Make a copy of the BufferQueue pointer to prevent other threads that may be
// resetting it from blowing away the queue prematurely while we're dealing
// with it.
auto LocalBQ = BQ;
// We write out the file in the following format:
//
// 1) We write down the XRay file header with version 1, type FDR_LOG.
// 2) Then we use the 'apply' member of the BufferQueue that's live, to
// ensure that at this point in time we write down the buffers that have
// been released (and marked "used") -- we dump the full buffer for now
// (fixed-sized) and let the tools reading the buffers deal with the data
// afterwards.
//
int Fd = -1;
{
__sanitizer::SpinMutexLock Guard(&FDROptionsMutex);
Fd = FDROptions.Fd;
}
if (Fd == -1)
Fd = getLogFD();
if (Fd == -1) {
auto Result = XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING;
__sanitizer::atomic_store(&LogFlushStatus, Result,
__sanitizer::memory_order_release);
return Result;
}
// Test for required CPU features and cache the cycle frequency
static bool TSCSupported = probeRequiredCPUFeatures();
static uint64_t CycleFrequency =
TSCSupported ? getTSCFrequency() : __xray::NanosecondsPerSecond;
XRayFileHeader Header;
Header.Version = 1;
Header.Type = FileTypes::FDR_LOG;
Header.CycleFrequency = CycleFrequency;
// FIXME: Actually check whether we have 'constant_tsc' and 'nonstop_tsc'
// before setting the values in the header.
Header.ConstantTSC = 1;
Header.NonstopTSC = 1;
Header.FdrData = FdrAdditionalHeaderData{LocalBQ->ConfiguredBufferSize()};
retryingWriteAll(Fd, reinterpret_cast<char *>(&Header),
reinterpret_cast<char *>(&Header) + sizeof(Header));
LocalBQ->apply([&](const BufferQueue::Buffer &B) {
uint64_t BufferSize = B.Size;
if (BufferSize > 0) {
retryingWriteAll(Fd, reinterpret_cast<char *>(B.Buffer),
reinterpret_cast<char *>(B.Buffer) + B.Size);
}
});
__sanitizer::atomic_store(&LogFlushStatus,
XRayLogFlushStatus::XRAY_LOG_FLUSHED,
__sanitizer::memory_order_release);
return XRayLogFlushStatus::XRAY_LOG_FLUSHED;
}
XRayLogInitStatus fdrLoggingFinalize() XRAY_NEVER_INSTRUMENT {
s32 CurrentStatus = XRayLogInitStatus::XRAY_LOG_INITIALIZED;
if (!__sanitizer::atomic_compare_exchange_strong(
&LoggingStatus, &CurrentStatus,
XRayLogInitStatus::XRAY_LOG_FINALIZING,
__sanitizer::memory_order_release))
return static_cast<XRayLogInitStatus>(CurrentStatus);
// Do special things to make the log finalize itself, and not allow any more
// operations to be performed until re-initialized.
BQ->finalize();
__sanitizer::atomic_store(&LoggingStatus,
XRayLogInitStatus::XRAY_LOG_FINALIZED,
__sanitizer::memory_order_release);
return XRayLogInitStatus::XRAY_LOG_FINALIZED;
}
XRayLogInitStatus fdrLoggingReset() XRAY_NEVER_INSTRUMENT {
s32 CurrentStatus = XRayLogInitStatus::XRAY_LOG_FINALIZED;
if (__sanitizer::atomic_compare_exchange_strong(
&LoggingStatus, &CurrentStatus,
XRayLogInitStatus::XRAY_LOG_INITIALIZED,
__sanitizer::memory_order_release))
return static_cast<XRayLogInitStatus>(CurrentStatus);
// Release the in-memory buffer queue.
BQ.reset();
// Spin until the flushing status is flushed.
s32 CurrentFlushingStatus = XRayLogFlushStatus::XRAY_LOG_FLUSHED;
while (__sanitizer::atomic_compare_exchange_weak(
&LogFlushStatus, &CurrentFlushingStatus,
XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING,
__sanitizer::memory_order_release)) {
if (CurrentFlushingStatus == XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING)
break;
CurrentFlushingStatus = XRayLogFlushStatus::XRAY_LOG_FLUSHED;
}
// At this point, we know that the status is flushed, and that we can assume
return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
}
static std::tuple<uint64_t, unsigned char>
getTimestamp() XRAY_NEVER_INSTRUMENT {
// We want to get the TSC as early as possible, so that we can check whether
// we've seen this CPU before. We also do it before we load anything else, to
// allow for forward progress with the scheduling.
unsigned char CPU;
uint64_t TSC;
// Test once for required CPU features
static bool TSCSupported = probeRequiredCPUFeatures();
if (TSCSupported) {
TSC = __xray::readTSC(CPU);
} else {
// FIXME: This code needs refactoring as it appears in multiple locations
timespec TS;
int result = clock_gettime(CLOCK_REALTIME, &TS);
if (result != 0) {
Report("clock_gettime(2) return %d, errno=%d", result, int(errno));
TS = {0, 0};
}
CPU = 0;
TSC = TS.tv_sec * __xray::NanosecondsPerSecond + TS.tv_nsec;
}
return std::make_tuple(TSC, CPU);
}
void fdrLoggingHandleArg0(int32_t FuncId,
XRayEntryType Entry) XRAY_NEVER_INSTRUMENT {
auto TSC_CPU = getTimestamp();
__xray_fdr_internal::processFunctionHook(FuncId, Entry, std::get<0>(TSC_CPU),
std::get<1>(TSC_CPU), clock_gettime,
LoggingStatus, BQ);
}
void fdrLoggingHandleCustomEvent(void *Event,
std::size_t EventSize) XRAY_NEVER_INSTRUMENT {
using namespace __xray_fdr_internal;
auto TSC_CPU = getTimestamp();
auto &TSC = std::get<0>(TSC_CPU);
auto &CPU = std::get<1>(TSC_CPU);
thread_local bool Running = false;
RecursionGuard Guard{Running};
if (!Guard) {
assert(Running && "RecursionGuard is buggy!");
return;
}
if (EventSize > std::numeric_limits<int32_t>::max()) {
using Empty = struct {};
static Empty Once = [&] {
Report("Event size too large = %zu ; > max = %d\n", EventSize,
std::numeric_limits<int32_t>::max());
return Empty();
}();
(void)Once;
}
int32_t ReducedEventSize = static_cast<int32_t>(EventSize);
if (!isLogInitializedAndReady(LocalBQ, TSC, CPU, clock_gettime))
return;
// Here we need to prepare the log to handle:
// - The metadata record we're going to write. (16 bytes)
// - The additional data we're going to write. Currently, that's the size of
// the event we're going to dump into the log as free-form bytes.
if (!prepareBuffer(clock_gettime, MetadataRecSize + EventSize)) {
LocalBQ = nullptr;
return;
}
// Write the custom event metadata record, which consists of the following
// information:
// - 8 bytes (64-bits) for the full TSC when the event started.
// - 4 bytes (32-bits) for the length of the data.
MetadataRecord CustomEvent;
CustomEvent.Type = uint8_t(RecordType::Metadata);
CustomEvent.RecordKind =
uint8_t(MetadataRecord::RecordKinds::CustomEventMarker);
constexpr auto TSCSize = sizeof(std::get<0>(TSC_CPU));
std::memcpy(&CustomEvent.Data, &ReducedEventSize, sizeof(int32_t));
std::memcpy(&CustomEvent.Data[sizeof(int32_t)], &TSC, TSCSize);
std::memcpy(RecordPtr, &CustomEvent, sizeof(CustomEvent));
RecordPtr += sizeof(CustomEvent);
std::memcpy(RecordPtr, Event, ReducedEventSize);
endBufferIfFull();
}
XRayLogInitStatus fdrLoggingInit(std::size_t BufferSize, std::size_t BufferMax,
void *Options,
size_t OptionsSize) XRAY_NEVER_INSTRUMENT {
if (OptionsSize != sizeof(FDRLoggingOptions))
return static_cast<XRayLogInitStatus>(__sanitizer::atomic_load(
&LoggingStatus, __sanitizer::memory_order_acquire));
s32 CurrentStatus = XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
if (!__sanitizer::atomic_compare_exchange_strong(
&LoggingStatus, &CurrentStatus,
XRayLogInitStatus::XRAY_LOG_INITIALIZING,
__sanitizer::memory_order_release))
return static_cast<XRayLogInitStatus>(CurrentStatus);
{
__sanitizer::SpinMutexLock Guard(&FDROptionsMutex);
memcpy(&FDROptions, Options, OptionsSize);
}
bool Success = false;
BQ = std::make_shared<BufferQueue>(BufferSize, BufferMax, Success);
if (!Success) {
Report("BufferQueue init failed.\n");
return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
}
// Install the actual handleArg0 handler after initialising the buffers.
__xray_set_handler(fdrLoggingHandleArg0);
__xray_set_customevent_handler(fdrLoggingHandleCustomEvent);
__sanitizer::atomic_store(&LoggingStatus,
XRayLogInitStatus::XRAY_LOG_INITIALIZED,
__sanitizer::memory_order_release);
Report("XRay FDR init successful.\n");
return XRayLogInitStatus::XRAY_LOG_INITIALIZED;
}
} // namespace __xray
static auto UNUSED Unused = [] {
using namespace __xray;
if (flags()->xray_fdr_log) {
XRayLogImpl Impl{
fdrLoggingInit, fdrLoggingFinalize, fdrLoggingHandleArg0,
fdrLoggingFlush,
};
__xray_set_log_impl(Impl);
}
return true;
}();