Date: Wed, 14 Jan 2004 12:50:34 +0000 (GMT) From: Richard Wendland <richard@starburst.demon.co.uk> To: sten.daniel.sorsdal@wan.no (=?iso-8859-1?Q?Sten_Daniel_S=F8rsdal?=) Cc: Adrian Penisoara <ady@freebsd.ady.ro> Subject: Re: Handling 100.000 packets/sec or more Message-ID: <200401141250.MAA00294@starburst.demon.co.uk> In-Reply-To: <0AF1BBDF1218F14E9B4CCE414744E70F5D9760@exchange.wanglobal.net> from "=?iso-8859-1?Q?Sten_Daniel_S=F8rsdal?=" at Jan 14, 2004 01:22:25 PM
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> device polling(8) really does help _alot_ for packet floods/storms. > for device polling to work properly (imho) you would need to set HZ to 1000. > I dont recommend any higher HZ on a PIII. Incidentally, setting HZ > 1000 would cause FreeBSD TCP to not comply with RFC1323, as it would make the TCP timestamp option clock tick faster than 1ms. RFC1323 4.2.2 specifies the clock rate to be in the range 1 ms to 1 sec per tick. Really the TCP timestamp option clock should be divorced from HZ before too long, as a time will come when people will want HZ > 1000. Actually a bit faster tick-rate is unlikely to run into much trouble in practice, but it will cause the PAWS algorithm to stop a long running TCP connection, see 4.2.3 of RFC1323. Richard -- Richard Wendland richard@wendland.org.uk
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