Date: Thu, 28 Oct 2004 11:11:24 -0400 From: John Baldwin <jhb@FreeBSD.org> To: Shunsuke SHINOMIYA <shino@fornext.org> Cc: obrien@FreeBSD.org Subject: Re: disabling interrupt storm protection Message-ID: <200410281111.24398.jhb@FreeBSD.org> In-Reply-To: <20041028165604.DCF8.SHINO@fornext.org> References: <20041022171924.73B3.SHINO@fornext.org> <200410271352.04069.jhb@FreeBSD.org> <20041028165604.DCF8.SHINO@fornext.org>
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On Thursday 28 October 2004 06:13 am, Shunsuke SHINOMIYA wrote: > Thank you, John. > > > Can you try this patch: > > > > --- //depot/vendor/freebsd/src/sys/kern/kern_intr.c 2004/09/05 02:10:52 > > +++ //depot/projects/smpng/sys/kern/kern_intr.c 2004/10/27 17:41:06 > > snip > > > First, can you test that your system works with the default threshold, > > and second, can you test that setting the threshold to zero disables the > > storm detection? > > I applied your patch to kern_intr.c, and then I transmitted the high > rate(148kpps) IP traffic to the box with the default threshold. But > storm protection was not invoked. > > It seem that sensitivity of the detector is fallen. > > I tried some patterns of the packet loss test(transmitting the packets > of the wire rate in 100Mbps to the box for 10 seconds. The frame size > of each packets is 64 octet). > > These results are as follows. > > Each `before' and `after' are outputs of `vmstat -i | grep em'. Please > observe the first numerical value(number of interrupts since system > startup). kern.hz is 100 at all trials. And `Interrupt Moderation', one > of the feature of em was disabled. > > ========== > o kern_intr.c applied your patch. > o hw.intr_storm_threshold=500(default) > > remark > o The test results of both 1st and 2nd trial are good, low packet loss > rate. A difference of both trials may be measurement error. > o Interrupt storm protections is not invoked. > o The interrupts rate of em0(input side) is about 25000 interrupts per > second during a trial. > o When hw.intr_storm_threshold=200, Interrupt storm protections is not > invoked. Excellent, thanks. I feared that the stuff under #ifdef HACK was causing false positives. I'll revert the code to the non-HACK version in HEAD and will get it into RELENG_5 at some point (though it is probably too late for 5.3.) -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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