The following reply was made to PR kern/179827; it has been noted by GNATS.
From: Adrian Chadd <adr...@freebsd.org> To: hiren panchasara <hiren.panchas...@gmail.com> Cc: bug-follo...@freebsd.org Subject: Re: kern/179827: [hwpmc] process-mode counters aren't correctly read on multi-core machines Date: Sat, 22 Jun 2013 13:23:24 -0700 Right. Do that but with the test running in another window, so you don't get the message overlap. THen look at how the results show lots of '0' from pmcstat, and then correlate that with the one-second "PMC,OPS" sample lines. See how whenever they're run whilst the process is running (ie, the last event was SWI) and it hasn't yet been de-scheduled. because it's still running, the saved counter is never updated with the PMC counter and subsequent reads (until it does get de-scheduled!) return the same cached value. Hence, lots of '0's, followed by a big, big counter value. adrian _______________________________________________ freebsd-bugs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
