Date: Thu, 01 Feb 2007 12:02:20 -0800 From: Julian Elischer <julian@elischer.org> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: FreeBSD Current <current@freebsd.org> Subject: Re: lock contention etc. Message-ID: <45C2474C.3080909@elischer.org> In-Reply-To: <17858.17285.523377.837244@grasshopper.cs.duke.edu> References: <45C24113.7000608@elischer.org> <17858.17285.523377.837244@grasshopper.cs.duke.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
Andrew Gallatin wrote: > Julian Elischer writes: > > I'm guessing that the extra system time represents a lot of > > contention somewhere. > > > > What is the best way to get actual numbers on this? > > The Dtrace lockstat tool is designed for this, and I've used it to > track down contention like this on Solaris. It seems to be on the > TODO list for the FreeBSD Dtrace port at > http://people.freebsd.org/~jb/dtrace/todo.html. I wonder how soon it > will arrive.. It is one of the things that I'm most looking forward > to. > > Drew I just realised that since this is an HTT machine the massive increase in user and system times between -j2 and -j4 is probably due to every thing running slower but over twice as many cpus.. The increase between -j1 and -j2 is more relevant and interesting I think. make -j 2 buildworld 2465.10 real 2958.94 user 1918.64 sys 2463.97 real 2968.43 user 1910.65 sys 2472.13 real 2978.64 user 1912.80 sys 2582.83 real 2965.51 user 2047.19 sys make -j 4 buildworld 2262.88 real 4322.31 user 3333.58 sys 2255.88 real 4330.32 user 3319.48 sys 2256.09 real 4318.84 user 3336.57 sys 2257.63 real 4338.34 user 3313.07 sys
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?45C2474C.3080909>