Description of problem:
We have an application that has a lot of threads and uses QReadWriteLocks to protect data that the threads are accessing. When our server is heavily loaded, the application spends about 60% of it's time in system time as opposed to user time. Further investigation showed that the QMutex class is calling sysconf(_SC_NPROCESSORS_ONLN) for each thread that tries to get a lock where that lock is already locked. Thus most of that system time is spent in this system call.
Version-Release number of selected component (if applicable):
This has been discussed upstream:
Created attachment 754181 [details]
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.