On a FreeBSD 7.1 SCHED_ULE kernel, I have a large number of files opened and mmapped (with MAP_NOSYNC option) for shared-memory communication between processes. Normally, memcpy() copies data into these shared-memory buffers in a reasonable amount of time closely related to the size of the copy (roughly 10us per 10KB). However, due to performance issues I've found that sometimes a memcpy() takes an abnormally long time (10ms for 40KB, and I suspect longer times occurring when I have not had monitoring enabled). The system doesn't seem to be in memory overcommit -- there is just a minor amount of swap in use, and I've not seen page-ins or page-outs while watching systat or vmstat.
Since I'm using MAP_NOSYNC, I would not expect the pager to flush dirty pages to disk and cause add delays. Any ideas where to look? Might it help to pin threads to CPUs in case a thread is getting moved to a different core? Thanks, Guy _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
