Process tests sometimes cause timeout on Linux #1
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This comment was originally written by fmalita@google.com Hanging stack trace: #0 0xf77c0430 in __kernel_vsyscall () We're calling unsafe functions (delete/free) in the SIGCHLD handler, deadlocking glibc's allocator. |
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This was fixed in https://code.google.com/p/dart/source/detail?r=325. Added Fixed label. |
This was referenced Jun 3, 2015
This was referenced Jun 3, 2015
This was referenced Jun 3, 2015
This was referenced Jun 3, 2015
This was referenced Jun 3, 2015
This was referenced Jun 3, 2015
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…ecks The (utf8) scanner currently has this thing where you give it a 0-terminated byte-array (i.e. you read the file, then allocate something that's 1 bigger, copy the data, then give it to the scanner) to 'avoid bounds checks'. Dart still has bounds checks though - they're just implicit. As for the string scanner ut gets a string, then creates a new string like `string + '\x00'` - so basically the same thing. This CL uses the 'vm:unsafe:no-bounds-checks' pragma, removing the implicit bounds checks, adding explicit bounds checks, saving ~73.6 mio instructions when compiling the CFE in the process: ``` Comparing snapshot #1 with snapshot #2 cycles:u: -0.9983% +/- 0.6563% (-174026333.30 +/- 114410028.98) instructions:u: -0.3416% +/- 0.0005% (-73659267.00 +/- 108567.20) branch-misses:u: -4.8952% +/- 2.2612% (-3172939.50 +/- 1465641.18) ``` With the scanner-benchmark with `--bytes` I get this: ``` msec task-clock:u: -1.2251% +/- 0.6355% (-50.64 +/- 26.27) cycles:u: -1.2376% +/- 0.6385% (-223642830.80 +/- 115393789.68) instructions:u: -2.8155% +/- 0.0000% (-1153243856.00 +/- 428.11) seconds time elapsed: -1.2165% +/- 0.6408% (-0.05 +/- 0.03) seconds user: -1.1539% +/- 0.6495% (-0.05 +/- 0.03) ``` With the scanner-benchmark with `--string` I get this: ``` msec task-clock:u: -7.6439% +/- 0.6628% (-366.08 +/- 31.74) page-faults:u: -95.0034% +/- 0.0014% (-228023.50 +/- 3.41) instructions:u: 2.1041% +/- 0.0000% (897941907.60 +/- 2082.79) branch-misses:u: 3.2994% +/- 1.4675% (3239735.30 +/- 1440940.88) seconds time elapsed: -7.6595% +/- 0.6610% (-0.37 +/- 0.03) seconds user: -0.8801% +/- 0.7676% (-0.04 +/- 0.03) seconds sys: -92.0140% +/- 2.8075% (-0.33 +/- 0.01) MarkSweep( old space) goes from 6 to 0 Notice combined GC time goes from 112 ms to 41 ms (notice only 1 run each). ``` Where I'll note that the 'vm:unsafe:no-bounds-checks' pragma doesn't (yet?) work for `String.codeUnitAt`. See https://dart-review.googlesource.com/c/sdk/+/384540 (and https://dart-review.googlesource.com/c/sdk/+/385201) for details. I assume the relatively big change here is caused by not allocating a new string with a 0-byte in the end each time. Note that the read-allocate-copy dance is still performed for the utf8 scanner in this CL as it requires changing all call-sites instead. It will be done in a follow-up CL where the "end-of-file" int will likely also be changed to `-1` to (I assume) allow for having the 0-byte in the middle of a file (see also the 10+ year old bug at #18090) Note: The pragma (currently?) only has effect in AOT and this change will (for the utf8 scanner) make the JIT version slower (probably by the same ~73.6 mio instructions as - at least in AOT - the implicit check is 6 instructions and the explicit one is 3 instructions). As the pragma doesn't work in the StringScanner anyway I expect the change to be somewhat equivalent there. Once the read-allocate-copy dance is also removed from the utf8 scanner I expect the combined result to be positive all around. Update: With https://dart-review.googlesource.com/c/sdk/+/385201 landed I get these changes: Compiling the CFE: ``` instructions:u: -0.4520% +/- 0.0002% (-98470955.29 +/- 42253.40) ``` Scanner benchmark with `--bytes`: ``` msec task-clock:u: -2.1758% +/- 0.2316% (-92.07 +/- 9.80) cycles:u: -2.1941% +/- 0.2283% (-405224983.11 +/- 42160655.88) instructions:u: -3.1049% +/- 0.0000% (-1272360052.95 +/- 706.54) branch-misses:u: 2.4718% +/- 0.5142% (2371345.23 +/- 493257.76) seconds time elapsed: -2.1761% +/- 0.2317% (-0.09 +/- 0.01) seconds user: -2.2071% +/- 0.2308% (-0.09 +/- 0.01) ``` Scanner benchmark with `--string`: ``` msec task-clock:u: -15.0073% +/- 0.2175% (-745.93 +/- 10.81) page-faults:u: -95.0035% +/- 0.0003% (-228024.25 +/- 0.81) cycles:u: -7.7986% +/- 0.2329% (-1558985588.99 +/- 46560962.79) instructions:u: -3.7054% +/- 0.0000% (-1581977447.66 +/- 481.68) branch-misses:u: -0.6880% +/- 0.5818% (-689453.22 +/- 583101.50) seconds time elapsed: -15.0198% +/- 0.2170% (-0.75 +/- 0.01) seconds user: -8.8149% +/- 0.2648% (-0.41 +/- 0.01) seconds sys: -94.1247% +/- 1.6444% (-0.34 +/- 0.01) MarkSweep( old space) goes from 6 to 0 ``` Change-Id: I524a21f488da7df5dc9d2cdf40112b84896ad3e0 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/383324 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com> Commit-Queue: Jens Johansen <jensj@google.com>
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See: b/374689139. https://dart-review.googlesource.com/c/sdk/+/390941 is blocking an SDK roll. Root cause: ``` Action threw an exception: type 'ConstructorMember' is not a subtype of type 'ConstructorFragment' in type cast #0 InterfaceTypeImpl.constructors2.<anonymous closure> (package:analyzer/src/dart/element/type.dart:569) #1 MappedListIterable.elementAt (dart:_internal/iterable.dart:435) #2 ListIterator.moveNext (dart:_internal/iterable.dart:364) #3 new _GrowableList._ofEfficientLengthIterable (dart:core-patch/growable_array.dart:189) #4 new _GrowableList.of (dart:core-patch/growable_array.dart:150) #5 new List.of (dart:core-patch/array_patch.dart:39) #6 ListIterable.toList (dart:_internal/iterable.dart:224) #7 InterfaceTypeImpl.constructors2 (package:analyzer/src/dart/element/type.dart:570) #8 _Visitor._hasConstConstructorInvocation (package:linter/src/rules/prefer_const_constructors_in_immutables.dart:110) #9 _Visitor.visitConstructorDeclaration (package:linter/src/rules/prefer_const_constructors_in_immutables.dart:58) ``` To verify the fix locally: ``` solo_test_X() async { await assertNoErrorsInCode(r''' class A<T> {} '''); var A = findElement.class_('A').instantiate( typeArguments: [intType], nullabilitySuffix: NullabilitySuffix.none, ); A.constructors2; } ``` Bug: b/374689139 Change-Id: I70034d938d840dc0c3939db27e7116164e4617e9 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/391483 Reviewed-by: Konstantin Shcheglov <scheglov@google.com> Commit-Queue: Phil Quitslund <pquitslund@google.com>
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## Added --cache to benchmarker.dart This doubles the amount of runs by running an additional round of `perf stat` runs outputting low level cache information: L1-icache-load-misses (instruction load misses), LLC-loads (last level cache loads, i.e. probably how many loads goes to L3 cache) and LLC-load-misses (last level cache load misses, i.e. how many loads goes to ram). I don't know if these are generally available, only that they are available on my machine. ## Added --silent to benchmarker.dart Some benchmarks output information to stdout which is great when running it by hand, but when running it via the benchmarker script it just pollutes the output: The benchmarker script et al measures what is supposed to be measured. This CL adds the `--silent` option to the benchmarker script which then won't print the stdout output from the benchmarkee. ## Output filename in benchmarker.dart This CL adds the filenames of the benchmarked snapshots in an attempt to avoid confusion. Example output before: ``` Comparing snapshot #1 with snapshot #2 ``` ``` Example output now: Comparing snapshot #1 (optimization_attempt_41.aot) with snapshot #2 (optimization_attempt_42.aot) ``` ## Utility to summarize --verbose-gc output Takes input from --verbose-gc from stdin and summarizes the time taken on GC and reports it back. Example: ``` $ out/ReleaseX64/dart --verbose-gc hello.dart 2> /dev/stdout 1> /dev/null | out/ReleaseX64/dart pkg/front_end/tool/verbose_gc_helper.dart 6.1 ``` Change-Id: I206f21cd8b42f844e60358aed711e676e453c77c Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/406845 Reviewed-by: Johnni Winther <johnniwinther@google.com> Commit-Queue: Jens Johansen <jensj@google.com>
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This is a possible fix for the following benign TSAN error:
WARNING: ThreadSanitizer: data race (pid=40436)
Read of size 8 at 0x7b7c000bfa48 by thread T6 (mutexes: write M0):
#0 dart::Page::object_end() const out/ReleaseTSANX64/../../runtime/vm/heap/page.h (dart+0x25ade83)
#1 dart::Page::used() const out/ReleaseTSANX64/../../runtime/vm/heap/page.h:107:34 (dart+0x25ade83)
#2 dart::SemiSpace::used_in_words() const out/ReleaseTSANX64/../../runtime/vm/heap/scavenger.h:46:18 (dart+0x25ade83)
#3 dart::Scavenger::UsedInWords() const out/ReleaseTSANX64/../../runtime/vm/heap/scavenger.h:157:17 (dart+0x25ade83)
#4 dart::GetProcessMemoryUsageHelper(dart::JSONStream*)::$_0::operator()(dart::IsolateGroup*) const out/ReleaseTSANX64/../../runtime/vm/service.cc:4729:50 (dart+0x25ade83)
Previous write of size 8 at 0x7b7c000bfa48 by thread T9:
#0 dart::Thread::set_top(unsigned long) out/ReleaseTSANX64/../../runtime/vm/thread.h:698:34 (dart+0x2622071)
#1 dart::Scavenger::TryAllocateFromTLAB(dart::Thread*, long) out/ReleaseTSANX64/../../runtime/vm/heap/scavenger.h:256:13 (dart+0x2622071)
#2 dart::Scavenger::TryAllocate(dart::Thread*, long) out/ReleaseTSANX64/../../runtime/vm/heap/scavenger.h:139:12 (dart+0x2622071)
#3 dart::Heap::AllocateNew(dart::Thread*, long) out/ReleaseTSANX64/../../runtime/vm/heap/heap.cc:84:27 (dart+0x2622071)
#4 dart::Heap::Allocate(dart::Thread*, long, dart::Heap::Space) out/ReleaseTSANX64/../../runtime/vm/heap/heap.h:87:16 (dart+0x2416cab)
TEST=ci
Change-Id: Id9077cff2c1143adf999b2b26c941701d63cd844
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/409180
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
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…terrupted
Thread interrupts can be disabled after thread interrupter decided to
interrupt a thread but before thread actually receives and handles
a signal.
This may cause a data race accessing a Sample between profiler which
initializes and adds a Sample and the main thread using
Profiler::sample_block_buffer() in the profiler unit tests.
This is a possible fix for the following benign TSAN error:
WARNING: ThreadSanitizer: data race (pid=5824)
Write of size 4 at 0x7f53e8e53a98 by thread T6:
#0 dart::Sample::set_thread_task(dart::Thread::TaskKind) out/ReleaseTSANX64/../../runtime/vm/profiler.h:325:12 (run_vm_tests+0x292cab2)
#1 dart::SetupSample(dart::Thread*, bool, unsigned long) out/ReleaseTSANX64/../../runtime/vm/profiler.cc:1226:11 (run_vm_tests+0x292cab2)
#2 dart::Profiler::SampleThread(dart::Thread*, dart::InterruptedThreadState const&) out/ReleaseTSANX64/../../runtime/vm/profiler.cc:1381:7 (run_vm_tests+0x292cab2)
#3 dart::ThreadInterrupterLinux::ThreadInterruptSignalHandler(int, siginfo_t*, void*) out/ReleaseTSANX64/../../runtime/vm/thread_interrupter_linux.cc:44:5 (run_vm_tests+0x2a064b0)
#4 __tsan::CallUserSignalHandler(__tsan::ThreadState*, bool, bool, int, __sanitizer::__sanitizer_siginfo*, void*) ../staging/llvm_build/tools/clang/stage2-bins/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:2122:5 (run_vm_tests+0x1fc057f)
#5 dart::Mutex::Unlock() out/ReleaseTSANX64/../../runtime/vm/os_thread_linux.cc:367:16 (run_vm_tests+0x2924b89)
Previous read of size 4 at 0x7f53e8e53a98 by main thread:
#0 dart::Sample::head_sample() const out/ReleaseTSANX64/../../runtime/vm/profiler.h:350:59 (run_vm_tests+0x22c70e7)
#1 dart::SampleBuffer::VisitSamples(dart::SampleVisitor*) out/ReleaseTSANX64/../../runtime/vm/profiler.h:589:20 (run_vm_tests+0x22c70e7)
#2 dart::SampleBlockBuffer::VisitSamples(dart::SampleVisitor*) out/ReleaseTSANX64/../../runtime/vm/profiler.h:752:18 (run_vm_tests+0x22c70e7)
#3 dart::Dart_TestHelperProfiler_GetSourceReport(dart::Thread*) out/ReleaseTSANX64/../../runtime/vm/profiler_test.cc:2241:26 (run_vm_tests+0x22c70e7)
#4 dart::Dart_TestProfiler_GetSourceReport() out/ReleaseTSANX64/../../runtime/vm/profiler_test.cc:2206:1 (run_vm_tests+0x22c70e7)
#5 dart::TestCase::Run() out/ReleaseTSANX64/../../runtime/bin/run_vm_tests.cc:53:3 (run_vm_tests+0x203fe6c)
--- Re-run this test:
python3 tools/test.py -n vm-tsan-linux-release-x64 vm/cc/Profiler_GetSourceReport
Also, this change is a possible fix for #44089.
TEST=ci
Change-Id: I8ad87c340580325cbd6e22b5f068e1e33b0a7d46
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/409460
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
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This test has a few independent calls to asyncExpectThrows which uses asyncStart/asyncEnd. However, multiple top-level asyncStart/asyncEnd are not allowed, which causes the following flaky error: ``` Unhandled exception: Exception: Fatal: asyncStart() was called even though we are done with testing.. This is most likely a bug in your test. #0 asyncStart (package:expect/async_helper.dart:53) #1 asyncExpectThrows (package:expect/async_helper.dart:140) #2 testMalformedAuthenticateHeaderWithAuthHandler.<anonymous closure> (file:///b/s/w/ir/cache/builder/sdk/tests/standalone/io/http_auth_digest_test.dart:345) #3 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:951) #4 Future._propagateToListeners (dart:async/future_impl.dart:980) #5 Future._completeWithValue (dart:async/future_impl.dart:723) #6 Future._asyncCompleteWithValue.<anonymous closure> (dart:async/future_impl.dart:807) #7 _microtaskLoop (dart:async/schedule_microtask.dart:40) #8 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49) #9 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:128) #10 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:195) --- Re-run this test: python3 tools/test.py -n vm-aot-ubsan-linux-release-x64 standalone/io/http_auth_digest_test ``` This change attempts to fix this by adding a top-level asyncStart/asyncEnd and also asyncStart/asyncEnd to the server start/shutdown to enclose each test case into asyncStart/asyncEnd and avoid printing "unittest-suite-success" marker before all test cases are finished. TEST=standalone/io/http_auth_digest_test Change-Id: I950e7c6c09f5c2144da874ab3be3cd3a130d3790 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/411086 Commit-Queue: Alexander Markov <alexmarkov@google.com> Reviewed-by: Alexander Aprelev <aam@google.com>
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Either of the process tests
ProcessExitTest.dart
ProcessSegfaultTest.dart
ProcessStartExceptionTest.dart
ProcessStderrTest.dart
ProcessStdoutTest.dart
can hang on Linux. It happens once every ~25 runs.
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