Date: Fri, 4 May 2007 18:03:40 +0300 From: Giorgos Keramidas <keramida@freebsd.org> To: Gavin Atkinson <gavin.atkinson@ury.york.ac.uk> Cc: freebsd-bugs@freebsd.org Subject: Re: bin/89762: [patch] top(1) startup is very slow on system with many users Message-ID: <20070504150339.GA22517@kobe.laptop> In-Reply-To: <200705041450.l44EoAJC003185@freefall.freebsd.org> References: <200705041450.l44EoAJC003185@freefall.freebsd.org>
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On 2007-05-04 14:50, Gavin Atkinson <gavin.atkinson@ury.york.ac.uk> wrote: > This is still a problem with 6.2-STABLE. On a 2.2GHz amd64 machine > with ~20,000 NIS users, "top -b" takes 74 seconds before displaying > any output and generates significant load on the NIS servers. > > wiggum# time top -b > last pid: 1742; load averages: 0.00, 0.00, 0.00 up 36+03:20:25 15:39:47 > 32 processes: 1 running, 31 sleeping > > Mem: 82M Active, 191M Inact, 108M Wired, 213M Buf, 1498M Free > Swap: 3072M Total, 3072M Free > [process list snipped] Can you truss/ptrace top at the time? I think it's trying to find the longest username string, to align the USERNAME column, and it queries the NIS server for *all* users. If that is the case, you should see a significant speedup when top runs with the -u option (but lose the functionality of seeing the username). We could probably 'trim' long usernames in the USERNAME column and add a character like '>' shown below: ------------------------------------------------------------------------ PID USERNAME THR PRI NICE SIZE RES STATE C TIME CPU COMMAND 4783 giorgosker> 1 96 0 294M 38244K CPU0 0 57:07 1.22% Xorg 22634 giorgosker> 1 96 0 11452K 9868K select 1 0:05 0.93% emacs 19084 giorgosker> 1 96 0 7256K 4176K select 0 2:49 0.88% xterm 960 root 1 96 0 3160K 864K select 0 12:51 0.00% powerd ------------------------------------------------------------------------ and keep a fixed length for the USERNAME column, but I am not sure if this would be an acceptablle UI change for top(1).
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