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https://issues.apache.org/jira/browse/XERCESC-2162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16719074#comment-16719074
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Sam Trahan edited comment on XERCESC-2162 at 12/12/18 3:33 PM:
---------------------------------------------------------------
I tried two tests and determined the problem was a few missing "volatile"
declarations. The test takes 21.05 seconds to pass, which suggests to me that
there is another problem somewhere.
Test 1: no optimization - works
Test 2: full debugging plus -O3 - fails just the same
(gdb) where
#0 0x00007ffe8e57fe2d in nanosleep () from /lib64/libc.so.6
#1 0x00007ffe8e57fcc4 in sleep () from /lib64/libc.so.6
#2 0x0000000000409912 in main (argc=-21216, argv=0x7fffffffad20)
at /a-very-long-path/.../ThreadTest.cpp:1334
The failure is here:
for (threadNum=0; threadNum < gRunInfo.numThreads; threadNum++)
{
if (gThreadInfo[threadNum].fHeartBeat == false) {
The fHeartBeat is optimized away because it was not declared volatile:
(gdb) print gThreadInfo[threadNum].fInProgress
value has been optimized out
There is no "volatile" protecting the variable, nor any data structure
containing it. Thus, the compiler is free to optimize it any way it wants to.
If I add "volatile" to these declarations, the thread tests pass, but take
21.05 seconds each to do it, which suggests there is another problem somewhere.
volatile bool fHeartBeat; // Set true by the thread each time
it finishes
// parsing a file.
volatile bool fInProgress; // Set to false by the thread when
parse in progress
volatile unsigned int fParses; // Number of parses completed.
volatile int fThreadNum; // Identifying number for this
thread.
was (Author: samueltrahannoaa):
I tried two tests:
1. no optimization - works
2. full debugging plus -O3 - fails just the same
(gdb) where
#0 0x00007ffe8e57fe2d in nanosleep () from /lib64/libc.so.6
#1 0x00007ffe8e57fcc4 in sleep () from /lib64/libc.so.6
#2 0x0000000000409912 in main (argc=-21216, argv=0x7fffffffad20)
at /a-very-long-path/.../ThreadTest.cpp:1334
The failure is here:
for (threadNum=0; threadNum < gRunInfo.numThreads; threadNum++)
{
if (gThreadInfo[threadNum].fHeartBeat == false) {
The fHeartBeat is optimized away, possibly because it was not declared volatile:
(gdb) print gThreadInfo[threadNum].fInProgress
value has been optimized out
There is no "volatile" protecting the variable, nor any data structure
containing it. Thus, the compiler is free to optimize it any way it wants to.
> ThreadTest freezes with Intel 17.0.5.239 and 18.0.1.163
> -------------------------------------------------------
>
> Key: XERCESC-2162
> URL: https://issues.apache.org/jira/browse/XERCESC-2162
> Project: Xerces-C++
> Issue Type: Bug
> Components: Samples/Tests
> Affects Versions: 3.2.2
> Environment: cat /etc/redhat-release
> Red Hat Enterprise Linux Server release 7.6 (Maipo)
> uname -a
> Linux tfe10 3.10.0-957.el7.x86_64 #1 SMP Thu Oct 4 20:48:51 UTC 2018 x86_64
> x86_64 x86_64 GNU/Linux
> Two versions of the Intel compiler suite were tried:
> icpc --version
> icpc (ICC) 17.0.5 20170817
> Copyright (C) 1985-2017 Intel Corporation. All rights reserved.
> icc --version
> icc (ICC) 17.0.5 20170817
> Copyright (C) 1985-2017 Intel Corporation. All rights reserved.
> icpc --version
> icpc (ICC) 18.0.1 20171018
> Copyright (C) 1985-2017 Intel Corporation. All rights reserved.
> icc --version
> icc (ICC) 18.0.1 20171018
> Copyright (C) 1985-2017 Intel Corporation. All rights reserved.
> Reporter: Sam Trahan
> Priority: Major
>
> The ThreadTest1 hangs forever when Xerces-C 3.2.2 is compiled using the Intel
> compiler versions 17.0.5.239 or 18.0.1.163. Running ThreadTest1 directly in
> gdb reveals that all ten threads exit, and main() is stuck in a wait loop
> calling sleep() forever.
> export CXX=icpc
> export CFLAGS='-fp-model precise'
> export CXXFLAGS='-fp-model precise'
> export CC=icc
> export CPP="icc -E"
> export CXXCPP="icpc -E"
> ./configure --prefix=/some/path
> make
> make check
> Changing the CXXFLAGS to this does not help:
> export CXXFLAGS='-fp-model precise -std=c++11'
> The last bit of output from "make check:"
> make[3]: Entering directory `/a-very-long-path/.../tests'
> PASS: scripts/DOMTest
> PASS: scripts/DOMMemTest
> PASS: scripts/RangeTest
> PASS: scripts/DOMTraversalTest
> XFAIL: scripts/XSerializerTest
> PASS: scripts/XSerializerTest1
> PASS: scripts/XSerializerTest2
> PASS: scripts/XSerializerTest3
> PASS: scripts/XSerializerTest4
> PASS: scripts/XSerializerTest5
> PASS: scripts/XSValueTest
> XFAIL: scripts/InitTermTest
> PASS: scripts/InitTermTest1
> PASS: scripts/InitTermTest2
> PASS: scripts/InitTermTest3
> XFAIL: scripts/ThreadTest
> The test hangs at that XFAIL: line. The "ps" command reveals ThreadTest1 is
> running:
> /a-very-long-path/.../tests/.libs/lt-ThreadTest -parser=sax -v=never -quiet
> -threads 10 -time 20 personal.xml
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