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//===-- 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 "Plugins/Process/POSIX/ProcessPOSIXLog.h"
#include "Procfs.h"
#include <optional>
using namespace lldb;
using namespace lldb_private;
using namespace process_linux;
using namespace llvm;
static bool IsTotalBufferLimitReached(ArrayRef<cpu_id_t> cores,
const TraceIntelPTStartRequest &request) {
uint64_t required = cores.size() * request.ipt_trace_size;
uint64_t limit = request.process_buffer_size_limit.value_or(
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. You can use "
"`sudo sysctl -w kernel.perf_event_paranoid=-1` for that.",
toString(std::move(error)).c_str());
}
Expected<std::unique_ptr<IntelPTMultiCoreTrace>>
IntelPTMultiCoreTrace::StartOnAllCores(const TraceIntelPTStartRequest &request,
NativeProcessProtocol &process,
std::optional<int> cgroup_fd) {
Expected<ArrayRef<cpu_id_t>> cpu_ids = GetAvailableLogicalCoreIDs();
if (!cpu_ids)
return cpu_ids.takeError();
if (IsTotalBufferLimitReached(*cpu_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.");
DenseMap<cpu_id_t, std::pair<IntelPTSingleBufferTrace, ContextSwitchTrace>>
traces;
for (cpu_id_t cpu_id : *cpu_ids) {
Expected<IntelPTSingleBufferTrace> core_trace =
IntelPTSingleBufferTrace::Start(request, /*tid=*/std::nullopt, cpu_id,
/*disabled=*/true, cgroup_fd);
if (!core_trace)
return IncludePerfEventParanoidMessageInError(core_trace.takeError());
if (Expected<PerfEvent> context_switch_trace =
CreateContextSwitchTracePerfEvent(cpu_id,
&core_trace->GetPerfEvent())) {
traces.try_emplace(cpu_id,
std::make_pair(std::move(*core_trace),
std::move(*context_switch_trace)));
} else {
return context_switch_trace.takeError();
}
}
return std::unique_ptr<IntelPTMultiCoreTrace>(
new IntelPTMultiCoreTrace(std::move(traces), process, (bool)cgroup_fd));
}
void IntelPTMultiCoreTrace::ForEachCore(
std::function<void(cpu_id_t cpu_id, IntelPTSingleBufferTrace &core_trace)>
callback) {
for (auto &it : m_traces_per_core)
callback(it.first, it.second.first);
}
void IntelPTMultiCoreTrace::ForEachCore(
std::function<void(cpu_id_t cpu_id, IntelPTSingleBufferTrace &intelpt_trace,
ContextSwitchTrace &context_switch_trace)>
callback) {
for (auto &it : m_traces_per_core)
callback(it.first, it.second.first, it.second.second);
}
void IntelPTMultiCoreTrace::ProcessDidStop() {
ForEachCore([](cpu_id_t cpu_id, IntelPTSingleBufferTrace &core_trace) {
if (Error err = core_trace.Pause()) {
LLDB_LOG_ERROR(GetLog(POSIXLog::Trace), std::move(err),
"Unable to pause the core trace for core {0}", cpu_id);
}
});
}
void IntelPTMultiCoreTrace::ProcessWillResume() {
ForEachCore([](cpu_id_t cpu_id, IntelPTSingleBufferTrace &core_trace) {
if (Error err = core_trace.Resume()) {
LLDB_LOG_ERROR(GetLog(POSIXLog::Trace), std::move(err),
"Unable to resume the core trace for core {0}", cpu_id);
}
});
}
TraceIntelPTGetStateResponse IntelPTMultiCoreTrace::GetState() {
TraceIntelPTGetStateResponse state;
state.using_cgroup_filtering = m_using_cgroup_filtering;
for (NativeThreadProtocol &thread : m_process.Threads())
state.traced_threads.push_back(TraceThreadState{thread.GetID(), {}});
state.cpus.emplace();
ForEachCore([&](lldb::cpu_id_t cpu_id,
const IntelPTSingleBufferTrace &core_trace,
const ContextSwitchTrace &context_switch_trace) {
state.cpus->push_back(
{cpu_id,
{{IntelPTDataKinds::kIptTrace, core_trace.GetIptTraceSize()},
{IntelPTDataKinds::kPerfContextSwitchTrace,
context_switch_trace.GetEffectiveDataBufferSize()}}});
});
return state;
}
bool IntelPTMultiCoreTrace::TracesThread(lldb::tid_t tid) const {
// All the process' threads are being traced automatically.
return (bool)m_process.GetThreadByID(tid);
}
llvm::Error IntelPTMultiCoreTrace::TraceStart(lldb::tid_t tid) {
// All the process' threads are being traced automatically.
if (!TracesThread(tid))
return createStringError(
inconvertibleErrorCode(),
"Thread %" PRIu64 " is not part of the target process", tid);
return Error::success();
}
Error IntelPTMultiCoreTrace::TraceStop(lldb::tid_t tid) {
return createStringError(inconvertibleErrorCode(),
"Can't stop tracing an individual thread when "
"per-cpu process tracing is enabled.");
}
Expected<std::optional<std::vector<uint8_t>>>
IntelPTMultiCoreTrace::TryGetBinaryData(
const TraceGetBinaryDataRequest &request) {
if (!request.cpu_id)
return std::nullopt;
auto it = m_traces_per_core.find(*request.cpu_id);
if (it == m_traces_per_core.end())
return createStringError(
inconvertibleErrorCode(),
formatv("Core {0} is not being traced", *request.cpu_id));
if (request.kind == IntelPTDataKinds::kIptTrace)
return it->second.first.GetIptTrace();
if (request.kind == IntelPTDataKinds::kPerfContextSwitchTrace)
return it->second.second.GetReadOnlyDataBuffer();
return std::nullopt;
}
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