https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54185
Lewis Hyatt <lhyatt at gmail dot com> changed:
What |Removed |Added
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CC| |lhyatt at gmail dot com
--- Comment #14 from Lewis Hyatt <lhyatt at gmail dot com> ---
Created attachment 49061
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49061&action=edit
Fix for random pthread_create() failures
Hello-
I have problems with the test case for this bug
(libstdc++-v3/testsuite/30_threads/condition_variable/54185.cc) failing
randomly. It happens more often with parallel make, and especially if running
the testsuite as a whole more than once in parallel. On my system at least
(x86-64, Ubuntu 18), it seems that pthread_create() will return EAGAIN
sometimes in any loop like the one this testcase uses:
for(int i = 0; i != 1000; ++i) {pthread_create(...); pthread_join(...);}
If such a loop is running in 3 or more processes in parallel it happens more
than 50% of the time. I am not sure what global resource gets used up, it
happens even if ulimit -a shows nothing being limited like processes or memory.
The attached patch fixes the failures for me; if thread creation fails, it just
gives up and moves on to the next iteration instead. I had to convert the
cond->wait() to the predicate form since it becomes possible for the notify to
take place prior to all threads calling wait.
I can submit this to gcc-patches if it makes sense to you? Thanks...
-Lewis
