Date: Sun, 25 Nov 2001 19:50:22 -0800 From: Kris Kennaway <kris@obsecurity.org> To: Sean Chittenden <sean@chittenden.org> Cc: Ian Dowse <iedowse@maths.tcd.ie>, Kris Kennaway <kris@obsecurity.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/usr.bin/tail forward.c Message-ID: <20011125195022.A8376@xor.obsecurity.org> In-Reply-To: <20011125193957.O20895@ninja1.internal>; from sean@chittenden.org on Sun, Nov 25, 2001 at 07:39:57PM -0800 References: <20011125153656.A94203@xor.obsecurity.org> <200111260038.aa52845@salmon.maths.tcd.ie> <2001@=> <20011125193957.O20895@ninja1.internal>
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--zYM0uCDKw75PZbzx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Nov 25, 2001 at 07:39:57PM -0800, Sean Chittenden wrote: > > >I dunno..the major use of tail -F is probably on logfiles which get > > >rotated infrequently. I can imagine that a site might want to > > >simultaneously monitor a large number of logfiles, but I don't know > > >what the CPU impact of that with your change would be..maybe not much. > > >If you tail -F, say, 100 simultaneous files, how much CPU does that > > >stat'ing use? > >=20 > > Running 100 "tail -F"s requires a pretty negliglible amount of CPU > > time (try it!), but kqueue does help by allowing the processes to > > be swapped out during any long pauses between file updates. > >=20 > > The reason for this change is simply to fix a particular use of > > tail that was broken by the addition of kqueue support. The current > > code gives us about half of the kqueue gains over the pre-kqueue > > version for the -F case (changes noticed quickly, polling frequency > > reduced by a factor of 4). Doing better is of course possible, but > > it doesn't seem particularly easy. Maybe the author of this patch > > (Maxim Konovalov) would be willing to have a go at it. >=20 > Why not wrap this functionality in a new CLI argument? If I'm tailing > over NFS or some non-kq enabled FS, then I'll turn on the flag > manually (ex: -N). Seems like this is a step backwards to me... -sc No, you're misunderstanding the nature of the change. Kris --zYM0uCDKw75PZbzx Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: For info see http://www.gnupg.org iD8DBQE8Abv8Wry0BWjoQKURAplSAJ4ixwCijMiLDAvwJ3o9kweMljK/SgCfXGI2 6U2E3eNoiCt5QOGBoDMInSA= =nXaD -----END PGP SIGNATURE----- --zYM0uCDKw75PZbzx-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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