[Lldb-commits] [lldb] 1300556 - Add unix signal hit counts to the target statistics.
Greg Clayton via lldb-commits
lldb-commits at lists.llvm.org
Wed Oct 27 22:31:22 PDT 2021
Author: Greg Clayton
Date: 2021-10-27T22:31:14-07:00
New Revision: 130055647922ffa9dd9abd5a838727773f73c48a
URL: https://github.com/llvm/llvm-project/commit/130055647922ffa9dd9abd5a838727773f73c48a
DIFF: https://github.com/llvm/llvm-project/commit/130055647922ffa9dd9abd5a838727773f73c48a.diff
LOG: Add unix signal hit counts to the target statistics.
Android and other platforms make wide use of signals when running applications and this can slow down debug sessions. Tracking this statistic can help us to determine why a debug session is slow.
The new data appears inside each target object and reports the signal hit counts:
"signals": [
{
"SIGSTOP": 1
},
{
"SIGUSR1": 1
}
],
Differential Revision: https://reviews.llvm.org/D112683
Added:
Modified:
lldb/include/lldb/Target/UnixSignals.h
lldb/source/Target/Statistics.cpp
lldb/source/Target/StopInfo.cpp
lldb/source/Target/UnixSignals.cpp
lldb/test/API/functionalities/signal/TestSendSignal.py
Removed:
################################################################################
diff --git a/lldb/include/lldb/Target/UnixSignals.h b/lldb/include/lldb/Target/UnixSignals.h
index 6fecdda12defc..1c91c9fdd4895 100644
--- a/lldb/include/lldb/Target/UnixSignals.h
+++ b/lldb/include/lldb/Target/UnixSignals.h
@@ -16,6 +16,7 @@
#include "lldb/Utility/ConstString.h"
#include "lldb/lldb-private.h"
#include "llvm/ADT/Optional.h"
+#include "llvm/Support/JSON.h"
namespace lldb_private {
@@ -80,6 +81,18 @@ class UnixSignals {
void RemoveSignal(int signo);
+ /// Track how many times signals are hit as stop reasons.
+ void IncrementSignalHitCount(int signo);
+
+ /// Get the hit count statistics for signals.
+ ///
+ /// Gettings statistics on the hit counts of signals can help explain why some
+ /// debug sessions are slow since each stop takes a few hundred ms and some
+ /// software use signals a lot and can cause slow debugging performance if
+ /// they are used too often. Even if a signal is not stopped at, it will auto
+ /// continue the process and a delay will happen.
+ llvm::json::Value GetHitCountStatistics() const;
+
// Returns a current version of the data stored in this class. Version gets
// incremented each time Set... method is called.
uint64_t GetVersion() const;
@@ -99,6 +112,7 @@ class UnixSignals {
ConstString m_name;
ConstString m_alias;
std::string m_description;
+ uint32_t m_hit_count = 0;
bool m_suppress : 1, m_stop : 1, m_notify : 1;
Signal(const char *name, bool default_suppress, bool default_stop,
diff --git a/lldb/source/Target/Statistics.cpp b/lldb/source/Target/Statistics.cpp
index a7207ac5d990d..41639264a949b 100644
--- a/lldb/source/Target/Statistics.cpp
+++ b/lldb/source/Target/Statistics.cpp
@@ -11,7 +11,9 @@
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Module.h"
#include "lldb/Symbol/SymbolFile.h"
+#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
+#include "lldb/Target/UnixSignals.h"
using namespace lldb;
using namespace lldb_private;
@@ -95,6 +97,13 @@ json::Value TargetStats::ToJSON(Target &target) {
}
}
+ ProcessSP process_sp = target.GetProcessSP();
+ if (process_sp) {
+ UnixSignalsSP unix_signals_sp = process_sp->GetUnixSignals();
+ if (unix_signals_sp)
+ target_metrics_json.try_emplace("signals",
+ unix_signals_sp->GetHitCountStatistics());
+ }
target_metrics_json.try_emplace("breakpoints", std::move(breakpoints_array));
target_metrics_json.try_emplace("totalBreakpointResolveTime",
totalBreakpointResolveTime);
diff --git a/lldb/source/Target/StopInfo.cpp b/lldb/source/Target/StopInfo.cpp
index 8258705990eb0..ef7dff4052ead 100644
--- a/lldb/source/Target/StopInfo.cpp
+++ b/lldb/source/Target/StopInfo.cpp
@@ -307,7 +307,7 @@ class StopInfoBreakpoint : public StopInfo {
// There's one other complication here. We may have run an async
// breakpoint callback that said we should stop. We only want to
- // override that if another breakpoint action says we shouldn't
+ // override that if another breakpoint action says we shouldn't
// stop. If nobody else has an opinion, then we should stop if the
// async callback says we should. An example of this is the async
// shared library load notification breakpoint and the setting
@@ -425,7 +425,7 @@ class StopInfoBreakpoint : public StopInfo {
}
internal_breakpoint = bp_loc_sp->GetBreakpoint().IsInternal();
-
+
// First run the precondition, but since the precondition is per
// breakpoint, only run it once per breakpoint.
std::pair<std::unordered_set<break_id_t>::iterator, bool> result =
@@ -535,7 +535,7 @@ class StopInfoBreakpoint : public StopInfo {
else
actually_said_continue = true;
}
-
+
// If we are going to stop for this breakpoint, then remove the
// breakpoint.
if (callback_says_stop && bp_loc_sp &&
@@ -579,7 +579,7 @@ class StopInfoBreakpoint : public StopInfo {
// Override should_stop decision when we have completed step plan
// additionally to the breakpoint
m_should_stop = true;
-
+
// We know we're stopping for a completed plan and we don't want to
// show the breakpoint stop, so compute the public stop info immediately
// here.
@@ -615,7 +615,7 @@ class StopInfoWatchpoint : public StopInfo {
// performing watchpoint actions.
class WatchpointSentry {
public:
- WatchpointSentry(ProcessSP p_sp, WatchpointSP w_sp) : process_sp(p_sp),
+ WatchpointSentry(ProcessSP p_sp, WatchpointSP w_sp) : process_sp(p_sp),
watchpoint_sp(w_sp) {
if (process_sp && watchpoint_sp) {
const bool notify = false;
@@ -624,7 +624,7 @@ class StopInfoWatchpoint : public StopInfo {
process_sp->AddPreResumeAction(SentryPreResumeAction, this);
}
}
-
+
void DoReenable() {
if (process_sp && watchpoint_sp) {
bool was_disabled = watchpoint_sp->IsDisabledDuringEphemeralMode();
@@ -637,13 +637,13 @@ class StopInfoWatchpoint : public StopInfo {
}
}
}
-
+
~WatchpointSentry() {
DoReenable();
if (process_sp)
process_sp->ClearPreResumeAction(SentryPreResumeAction, this);
}
-
+
static bool SentryPreResumeAction(void *sentry_void) {
WatchpointSentry *sentry = (WatchpointSentry *) sentry_void;
sentry->DoReenable();
@@ -724,14 +724,14 @@ class StopInfoWatchpoint : public StopInfo {
// course of this code. Also by default we're going to stop, so set that
// here.
m_should_stop = true;
-
+
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
WatchpointSP wp_sp(
thread_sp->CalculateTarget()->GetWatchpointList().FindByID(
- GetValue()));
+ GetValue()));
if (wp_sp) {
ExecutionContext exe_ctx(thread_sp->GetStackFrameAtIndex(0));
ProcessSP process_sp = exe_ctx.GetProcessSP();
@@ -889,12 +889,12 @@ class StopInfoWatchpoint : public StopInfo {
bool old_async = debugger.GetAsyncExecution();
debugger.SetAsyncExecution(true);
-
+
StoppointCallbackContext context(event_ptr, exe_ctx, false);
bool stop_requested = wp_sp->InvokeCallback(&context);
-
+
debugger.SetAsyncExecution(old_async);
-
+
// Also make sure that the callback hasn't continued the target. If
// it did, when we'll set m_should_stop to false and get out of here.
if (HasTargetRunSinceMe())
@@ -1272,6 +1272,7 @@ StopInfo::CreateStopReasonWithWatchpointID(Thread &thread, break_id_t watch_id,
StopInfoSP StopInfo::CreateStopReasonWithSignal(Thread &thread, int signo,
const char *description) {
+ thread.GetProcess()->GetUnixSignals()->IncrementSignalHitCount(signo);
return StopInfoSP(new StopInfoUnixSignal(thread, signo, description));
}
diff --git a/lldb/source/Target/UnixSignals.cpp b/lldb/source/Target/UnixSignals.cpp
index 6e857e6618d39..26ff0bbd3825f 100644
--- a/lldb/source/Target/UnixSignals.cpp
+++ b/lldb/source/Target/UnixSignals.cpp
@@ -15,6 +15,7 @@
#include "lldb/Utility/ArchSpec.h"
using namespace lldb_private;
+using namespace llvm;
UnixSignals::Signal::Signal(const char *name, bool default_suppress,
bool default_stop, bool default_notify,
@@ -312,3 +313,20 @@ UnixSignals::GetFilteredSignals(llvm::Optional<bool> should_suppress,
return result;
}
+
+void UnixSignals::IncrementSignalHitCount(int signo) {
+ collection::iterator pos = m_signals.find(signo);
+ if (pos != m_signals.end())
+ pos->second.m_hit_count += 1;
+}
+
+json::Value UnixSignals::GetHitCountStatistics() const {
+ json::Array json_signals;
+ for (const auto &pair: m_signals) {
+ if (pair.second.m_hit_count > 0)
+ json_signals.emplace_back(json::Object{
+ { pair.second.m_name.GetCString(), pair.second.m_hit_count }
+ });
+ }
+ return std::move(json_signals);
+}
diff --git a/lldb/test/API/functionalities/signal/TestSendSignal.py b/lldb/test/API/functionalities/signal/TestSendSignal.py
index f1ccc6d024fb3..88caa2daaf42e 100644
--- a/lldb/test/API/functionalities/signal/TestSendSignal.py
+++ b/lldb/test/API/functionalities/signal/TestSendSignal.py
@@ -95,6 +95,10 @@ def test_with_run_command(self):
thread.GetStopReasonDataAtIndex(0), lldbutil.get_signal_number('SIGUSR1'),
"The stop signal was SIGUSR1")
+ self.match("statistics dump",
+ [r'"signals": \[', r'"SIGUSR1": 1'])
+
+
def match_state(self, process_listener, expected_state):
num_seconds = 5
broadcaster = self.process().GetBroadcaster()
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