On Fri, Jan 2, 2015 at 12:24 PM, Konstantin Belousov kostikbel@gmail.com wrote:
On Fri, Jan 02, 2015 at 09:09:34AM -0500, grarpamp wrote:
Some recent FreeBSD related questions in this app area.
What is the question ?
As a background, I can repeat that FreeBSD implements syscall-less gettimeofday() and clock_gettime() for x86 machines which have usable RDTSC. The selection of the timecounter can be verified by sysctl kern.timecounter.hardware, and enabled by default fast gettimeofday(2) can be checked by sysctl kern.timecounter.fast_gettime.
On some Nehalem machine, I see it doing ~30M calls/sec with enabled fast_gettime, and ~6.25M calls/sec with disabled fast_gettime. This is measured on 2.8GHz Core i7 930 with src/tools/tools/syscall_timing.
Check your timecounter hardware. Since it was noted that the tests were done in VM, check the quality of RDTSC emulation in your hypervisor.
https://lists.torproject.org/pipermail/tor-dev/2015-January/thread.html http://docs.freebsd.org/mail/current/freebsd-performance.html
Maybe I can just refer non subscribers out to the two lists above that way in case anyone sees anything interesting they can join/comment as desired.
Background might be that Tor operators have some large relays on *BSD and were looking to validate, and ways to improve, performance there.
Cheers.
https://lists.torproject.org/pipermail/tor-relays/ https://lists.torproject.org/pipermail/tor-talk/