Date: Mon, 22 Sep 1997 09:19:48 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Nate Williams <nate@mt.sri.com> Cc: "Justin T. Gibbs" <gibbs@plutotech.com>, current@FreeBSD.ORG Subject: Re: cvs commit: src/sys/conf files src/sys/dev/vx if_vx.c if_vxreg.h src/sys/i386/apm apm.c src/sys/i386/conf GENERIC files.i386 src/sys/i386/eisa 3c5x9.c aha1742.c aic7770.c bt74x.c eisaconf.c eisaconf.h if_fea.c if_vx_eisa.c src/sys/i386/i386 autoconf.c ... Message-ID: <316.874912788@critter.freebsd.dk> In-Reply-To: Your message of "Sun, 21 Sep 1997 23:05:20 MDT." <199709220505.XAA29116@rocky.mt.sri.com>
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In message <199709220505.XAA29116@rocky.mt.sri.com>, Nate Williams writes: >> 2) New callout interface. This gives O(1) insertion and removal of >> callouts and an O(hash chain length) amount of work to be performed >> in softclock. >... >> the O(n) hit on insertion and removal was painful. The networking >> code is another area that may want to make heavier use of callouts >> now that it is efficient to do so. If you are maintaining a driver >> outside of the tree, or need to update a driver I missed, see the >> timeout.9 man page for details on how the new interface works. For >> those who want to read more about the new implementation, here's a >> pointer to the original paper: >> >> http://www.cs.berkeley.edu/~amc/research/timer/ > >I just read the paper, and it's interesting, but they never give results >based on what the kernel does now. Basically, it's pretty easy to say >that registering/unregistering timers is now much faster, but given that >things can take longer in softclock(), it's not obvious (at least to me) >that this is a win overall, since we call softlock a *heck* of alot more >than we register/de-register timeout/callouts. According to my measurements on my laptop, it's a wash. That means that it will be a win on any other machine I belive. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop."
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