Use absl::GetStackTrace for slow task profiler (#7374)

* Make SlowTask workload runnable in joshua

* Remove SignalSafeUnwind, and use absl::GetStackTrace for slow task profiler

fdbserver/workloads/SlowTaskWorkload.actor.cpp

@@ -22,7 +22,6 @@
 
 #include "contrib/fmt-8.1.1/include/fmt/format.h"
 #include "fdbserver/workloads/workloads.actor.h"
-#include "flow/SignalSafeUnwind.h"
 #include "flow/actorcompiler.h" // This must be the last #include.
 
 // Stress test the slow task profiler or flow profiler
@@ -43,24 +42,22 @@ struct SlowTaskWorkload : TestWorkload {
 
 	ACTOR static Future<Void> go() {
 		wait(delay(1));
-		int64_t phc = dl_iterate_phdr_calls;
 		int64_t startProfilesDeferred = getNumProfilesDeferred();
 		int64_t startProfilesOverflowed = getNumProfilesOverflowed();
 		int64_t startProfilesCaptured = getNumProfilesCaptured();
 		int64_t exc = 0;
-		fprintf(stderr, "Slow task starting\n");
+		fprintf(stdout, "Slow task starting\n");
 		for (int i = 0; i < 10; i++) {
-			fprintf(stderr, "  %d\n", i);
+			fprintf(stdout, "  %d\n", i);
 			double end = timer() + 1;
 			while (timer() < end) {
 				do_slow_exception_thing(&exc);
 			}
 		}
-		fmt::print(stderr,
+		fmt::print(stdout,
-		           "Slow task complete: {0} exceptions; {1} calls to dl_iterate_phdr, {2}"
+		           "Slow task complete: {0} exceptions; {1} profiles deferred, {2} profiles overflowed, {3} profiles "
-		           " profiles deferred, {3} profiles overflowed, {4} profiles captured\n",
+		           "captured\n",
 		           exc,
-		           dl_iterate_phdr_calls - phc,
 		           getNumProfilesDeferred() - startProfilesDeferred,
 		           getNumProfilesOverflowed() - startProfilesOverflowed,
 		           getNumProfilesCaptured() - startProfilesCaptured);

flow/CMakeLists.txt

@@ -62,8 +62,6 @@ set(FLOW_SRCS
   Profiler.h
   ScopeExit.h
   SendBufferIterator.h
-  SignalSafeUnwind.cpp
-  SignalSafeUnwind.h
   SimpleOpt.h
   StreamCipher.cpp
   StreamCipher.h

flow/Net2.actor.cpp

@@ -89,10 +89,6 @@ void initProfiling() {
 	net2backtraces = new volatile void*[net2backtraces_max];
 	other_backtraces = new volatile void*[net2backtraces_max];
 
-	// According to folk wisdom, calling this once before setting up the signal handler makes
-	// it async signal safe in practice :-/
-	backtrace(const_cast<void**>(other_backtraces), net2backtraces_max);
-
 	sigemptyset(&sigprof_set);
 	sigaddset(&sigprof_set, SIGPROF);
 }

flow/Platform.actor.cpp

@@ -3738,7 +3738,7 @@ void profileHandler(int sig) {
 	ps->timestamp = checkThreadTime.is_lock_free() ? checkThreadTime.load() : 0;
 
 	// SOMEDAY: should we limit the maximum number of frames from backtrace beyond just available space?
-	size_t size = backtrace(ps->frames, net2backtraces_max - net2backtraces_offset - 2);
+	size_t size = platform::raw_backtrace(ps->frames, net2backtraces_max - net2backtraces_offset - 2);
 
 	ps->length = size;
 

flow/SignalSafeUnwind.cpp

@@ -1,55 +0,0 @@
-/*
- * SignalSafeUnwind.cpp
- *
- * This source file is part of the FoundationDB open source project
- *
- * Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "flow/SignalSafeUnwind.h"
-
-int64_t dl_iterate_phdr_calls = 0;
-
-#if defined(__linux__) && !defined(USE_SANITIZER)
-
-#include <link.h>
-#include <mutex>
-
-static int (*chain_dl_iterate_phdr)(int (*callback)(struct dl_phdr_info* info, size_t size, void* data),
-                                    void* data) = nullptr;
-
-static void initChain() {
-	static std::once_flag flag;
-
-	// Ensure that chain_dl_iterate_phdr points to the "real" function that we are overriding
-	std::call_once(flag, []() { *(void**)&chain_dl_iterate_phdr = dlsym(RTLD_NEXT, "dl_iterate_phdr"); });
-
-	if (!chain_dl_iterate_phdr) {
-		criticalError(FDB_EXIT_ERROR, "SignalSafeUnwindError", "Unable to find dl_iterate_phdr symbol");
-	}
-}
-
-// This overrides the function in libc!
-extern "C" int dl_iterate_phdr(int (*callback)(struct dl_phdr_info* info, size_t size, void* data), void* data) {
-	interlockedIncrement64(&dl_iterate_phdr_calls);
-
-	initChain();
-
-	setProfilingEnabled(0);
-	int result = chain_dl_iterate_phdr(callback, data);
-	setProfilingEnabled(1);
-	return result;
-}
-#endif

flow/SignalSafeUnwind.h

@@ -1,30 +0,0 @@
-/*
- * SignalSafeUnwind.h
- *
- * This source file is part of the FoundationDB open source project
- *
- * Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef FLOW_SIGNAL_SAFE_UNWIND
-#define FLOW_SIGNAL_SAFE_UNWIND
-#pragma once
-
-#include "flow/Platform.h"
-
-// This can be used by tests to measure the number of calls to dl_iterate_phdr intercepted
-extern int64_t dl_iterate_phdr_calls;
-
-#endif

tests/CMakeLists.txt

@@ -94,7 +94,7 @@ if(WITH_PYTHON)
   else()
     add_fdb_test(TEST_FILES SimpleExternalTest.txt IGNORE)
   endif()
-  add_fdb_test(TEST_FILES SlowTask.txt IGNORE)
+  add_fdb_test(TEST_FILES noSim/SlowTask.txt IGNORE)
   add_fdb_test(TEST_FILES SpecificUnitTest.txt IGNORE)
   add_fdb_test(TEST_FILES StorageMetricsSampleTests.txt IGNORE)
   add_fdb_test(TEST_FILES WorkerTests.txt IGNORE)

tests/noSim/SlowTask.txt

@@ -1,2 +1,3 @@
+useDB=false
 testTitle=Slow Task Stress
     testName=SlowTaskWorkload