Date: Wed, 13 Oct 1999 10:25:16 -0700 (PDT) From: John Polstra <jdp@polstra.com> To: aron@cs.rice.edu Cc: hackers@freebsd.org Subject: Re: paper on fine-grained OS timers Message-ID: <199910131725.KAA04762@vashon.polstra.com> In-Reply-To: <199910121552.KAA16014@cs.rice.edu> References: <199910121552.KAA16014@cs.rice.edu>
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In article <199910121552.KAA16014@cs.rice.edu>, Mohit Aron <aron@cs.rice.edu> wrote: > I'd like to tell the BSD community about my paper entitled > "Soft timers: efficient microsecond software timer support for network > processing" that's going to appear in SOSP 1999. The abstract for the paper > is attached below. The gzip'd postcript for the paper can be downloaded from: > http://www.cs.rice.edu/~aron/papers/soft-timers.ps.gz This looks like it would be a nice solution to a known problem with dummynet. From dummynet(4): dummynet performs its task once per timer tick. The granularity of operation is thus controlled by the kernel option options HZ whose default value (100) means a granularity of 10ms. For an accurate simulation of high data rates it might be necessary to reduce the timer granularity to 1ms or less. Consider, however, that some interfaces using programmed I/O may require a considerable time to output packets. So, re- ducing the granularity too much might actually cause ticks to be missed thus reducing the accuracy of operation. John -- John Polstra jdp@polstra.com John D. Polstra & Co., Inc. Seattle, Washington USA "No matter how cynical I get, I just can't keep up." -- Nora Ephron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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