Date: Sun, 2 Aug 2009 20:58:14 +0100 From: "Robert N. M. Watson" <rwatson@FreeBSD.org> To: Alfred Perlstein <alfred@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Navdeep Parhar <nparhar@gmail.com>, Hans Petter Selasky <hselasky@c2i.net> Subject: Re: svn commit: r195960 - in head/sys/dev/usb: . controller input Message-ID: <134A728D-F2F4-4951-81D8-704CC2DB6F9F@FreeBSD.org> In-Reply-To: <20090802192902.GS47463@elvis.mu.org> References: <200907300014.n6U0EZ77086341@svn.freebsd.org> <d04e16b70907310045y635245efob33b10464c22524f@mail.gmail.com> <20090731212140.GK47463@elvis.mu.org> <200908010615.02972.hselasky@c2i.net> <alpine.BSF.2.00.0908012313500.1507@fledge.watson.org> <20090802192902.GS47463@elvis.mu.org>
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On 2 Aug 2009, at 20:29, Alfred Perlstein wrote: > * Robert Watson <rwatson@FreeBSD.org> [090801 15:15] wrote: >> >> On Sat, 1 Aug 2009, Hans Petter Selasky wrote: >> >>>>> This has slowed down core dumps very significantly. What used >>>>> to take >>>>> 10-15s on my system now takes around 3 minutes. A simple test >>>>> is to >>>>> break into ddb and "call doadump" with or without this rev. I >>>>> have a >>>>> serial console on this machine and so I can use ddb whether the >>>>> attached >>>>> USB keyboard works or not. >>> >>> It's because there is a DELAY(1000) in the UKBD's polling routine >>> so that >>> key- repeating will work, no magic. >> >> Given a choice between dumping 10x faster and having automatic key >> repeat >> in DDB, I'd lean towards the former. :-) >> > > Robert, and *@freebsd.org, > > Hans should be back in a day or so to address this. If critical I can > probably back out the offending code, but I think it makes sense to > wait a few days more for a more comprehensive fix. That's my feeling too -- however, I think it would be useful to generate a small concept test patch that disables the key repeat behavior and see if it restores some/all performance. Scott's argument suggests only some, but perhaps we'd get quite a bit, which is what we're looking for. We wouldn't commit the patch but it would let us know we're on the right track. Robert
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