1637545f68
When tracing on per-core mode, we are tracing all processes, which means that after hitting a breakpoint, our process will stop running (thus producing no more tracing data) but other processes will continue writing to our trace buffers. This causes a big data loss for our trace. As a way to remediate this, I'm adding some logic to pause and unpause tracing based on the target's state. The earlier we do it the better, however, I'm not adding the trigger at the earliest possible point for simplicity of this diff. Later we can improve that part. Differential Revision: https://reviews.llvm.org/D124962
97 lines
3.4 KiB
C++
97 lines
3.4 KiB
C++
//===-- IntelPTMultiCoreTrace.cpp -----------------------------------------===//
|
|
//
|
|
// 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "IntelPTMultiCoreTrace.h"
|
|
|
|
#include "Procfs.h"
|
|
|
|
#include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
|
|
|
|
using namespace lldb;
|
|
using namespace lldb_private;
|
|
using namespace process_linux;
|
|
using namespace llvm;
|
|
|
|
static bool IsTotalBufferLimitReached(ArrayRef<core_id_t> cores,
|
|
const TraceIntelPTStartRequest &request) {
|
|
uint64_t required = cores.size() * request.trace_buffer_size;
|
|
uint64_t limit = request.process_buffer_size_limit.getValueOr(
|
|
std::numeric_limits<uint64_t>::max());
|
|
return required > limit;
|
|
}
|
|
|
|
static Error IncludePerfEventParanoidMessageInError(Error &&error) {
|
|
return createStringError(
|
|
inconvertibleErrorCode(),
|
|
"%s\nYou might need to rerun as sudo or to set "
|
|
"/proc/sys/kernel/perf_event_paranoid to a value of 0 or -1.",
|
|
toString(std::move(error)).c_str());
|
|
}
|
|
|
|
Expected<IntelPTMultiCoreTraceUP> IntelPTMultiCoreTrace::StartOnAllCores(
|
|
const TraceIntelPTStartRequest &request) {
|
|
Expected<ArrayRef<core_id_t>> core_ids = GetAvailableLogicalCoreIDs();
|
|
if (!core_ids)
|
|
return core_ids.takeError();
|
|
|
|
if (IsTotalBufferLimitReached(*core_ids, request))
|
|
return createStringError(
|
|
inconvertibleErrorCode(),
|
|
"The process can't be traced because the process trace size limit "
|
|
"has been reached. Consider retracing with a higher limit.");
|
|
|
|
llvm::DenseMap<core_id_t, IntelPTSingleBufferTraceUP> buffers;
|
|
for (core_id_t core_id : *core_ids) {
|
|
if (Expected<IntelPTSingleBufferTraceUP> core_trace =
|
|
IntelPTSingleBufferTrace::Start(request, /*tid=*/None, core_id,
|
|
TraceCollectionState::Paused))
|
|
buffers.try_emplace(core_id, std::move(*core_trace));
|
|
else
|
|
return IncludePerfEventParanoidMessageInError(core_trace.takeError());
|
|
}
|
|
|
|
return IntelPTMultiCoreTraceUP(new IntelPTMultiCoreTrace(std::move(buffers)));
|
|
}
|
|
|
|
void IntelPTMultiCoreTrace::ForEachCore(
|
|
std::function<void(core_id_t core_id, IntelPTSingleBufferTrace &core_trace)>
|
|
callback) {
|
|
for (auto &it : m_traces_per_core)
|
|
callback(it.first, *it.second);
|
|
}
|
|
|
|
void IntelPTMultiCoreTrace::OnProcessStateChanged(lldb::StateType state) {
|
|
if (m_process_state == state)
|
|
return;
|
|
switch (state) {
|
|
case eStateStopped:
|
|
case eStateExited: {
|
|
ForEachCore([](core_id_t core_id, IntelPTSingleBufferTrace &core_trace) {
|
|
if (Error err =
|
|
core_trace.ChangeCollectionState(TraceCollectionState::Paused)) {
|
|
LLDB_LOG_ERROR(GetLog(POSIXLog::Trace), std::move(err),
|
|
"Unable to pause the core trace for core {0}", core_id);
|
|
}
|
|
});
|
|
break;
|
|
}
|
|
case eStateRunning: {
|
|
ForEachCore([](core_id_t core_id, IntelPTSingleBufferTrace &core_trace) {
|
|
if (Error err =
|
|
core_trace.ChangeCollectionState(TraceCollectionState::Running)) {
|
|
LLDB_LOG_ERROR(GetLog(POSIXLog::Trace), std::move(err),
|
|
"Unable to resume the core trace for core {0}", core_id);
|
|
}
|
|
});
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|