On Fri Sep 9 11, Paul Ambrose wrote: > what version of chromium are you using? > I use chromium-13.0.782.215 on amd64 8.2-stable, the gettimeofday call is > far less than 20000 per second, about 20 per second, but I notice old > version has this bug, but latest version has fixed it. Maybe you should > update your chromium and try again.
i'm running chromium-13.0.782.220 and sudo ktrace -di -tc -p1758; sleep 1; sudo ktrace -C; sudo kdump|grep gettimeofday|wc -l gives me 3056. so the number has decresed, yet i don't see why chromium needs to call gettimeofday(2) or any library function that triggers it more than 3000 times a second. also sudo ktrace -di -tc -p1758; sleep 1; sudo ktrace -C; sudo kdump|wc -l is returning 16695. that also seems like a pretty high syscall count in general for only 1 second. cheers. alex > > Firefox 5 and 6 has more gettimeofday call than 20000 per second on my > amd64-8.2-stable box. > > 2011/9/7 Alexander Best <arun...@freebsd.org> > > > On Wed Sep 7 11, Peter Jeremy wrote: > > > On 2011-Sep-06 16:44:48 -0600, Manish Vachharajani < > > mani...@lineratesystems.com> wrote: > > > >Under 7.3 (haven't checked 8 or 9) this issue crops up because the > > > >time system call calls gettimeofday under the hood (see > > > >lib/libc/gen/time.c). As a result, the kernel tries to get an > > > >accurate subsecond resolution time that simply gets chopped to the > > > >nearest second. > > > > > > Under 8.x and later, time(3) uses clock_gettime(CLOCK_SECOND,...) > > > rather than gettimeofday(). This is intended to be much cheaper > > > than gettimeofday(). > > > > > > On 2011-Sep-06 21:15:55 -0400, Rayson Ho <raysonlo...@gmail.com> wrote: > > > >IMO, the time returned by gettimeofday does not need to be high > > > >precision. There are higher resolution time APIs on Linux and I > > > >believe the application programmers know when to use the slower but > > > >more accurate clock API. > > > > > > There are 3 standard APIs for returning time of day: > > > time(3) provides second precision > > > gettimeofday(2) provides microsecond precision > > > clock_gettime(2) provides nanosecond precision > > > > > > By default, FreeBSD attempts to provide resolution as close as > > > possible to the precision - which makes the 2 system calls fairly > > > expensive. In order to reduce the cost where the resolution isn't > > > important, FreeBSD provides several non-standard clock types for > > > clock_gettime(2). This approach differs from Linux - and it seems > > > that there is a non-trivial body of code that assumes that calling > > > gettimeofday() is very cheap. > > > > > > There is probably a good case for an API that provides a resolution > > > of the order of a tick but there is no standard for this. > > > > chromium is triggering ~20.000 gettimeofday(2) calls per second on my > > machine. > > i'm running CURRENT on amd64. > > > > cheers. > > alex > > > > > > > > -- > > > Peter Jeremy > > > > > > _______________________________________________ > > 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" > > _______________________________________________ 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"
