Date: Thu, 17 Jul 1997 15:08:46 -0600 From: Steve Passe <smp@csn.net> To: Poul-Henning Kamp <phk@dk.tfs.com> Cc: smp@freebsd.org, Peter Wemm <peter@spinner.dialix.com.au>, dyson@freebsd.org Subject: Re: pushdown of "giant lock" Message-ID: <199707172108.PAA15231@Ilsa.StevesCafe.com> In-Reply-To: Your message of "Thu, 17 Jul 1997 22:27:40 %2B0200." <18580.869171260@critter.dk.tfs.com>
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Hi, > >DESIGN PROPOSAL: > > ... > As the guy who's done it before and in this case did it last time, let > me add some other input to this topic: > > 1. Add a optional (possibly compile-option) circular buffer which will > record the lock actions. somewher I have debug code for the lock that uses an XXX-kbyte buffer of INTs to record each lock transition, allowing you to record the last XXX,000 transitions if you wish. I also built a tool to scarf this buffer and present it in a nice formatted fashon. It was quite useful for getting the XXPRESS system working (first >2 CPU system to work properly). --- > 2. Add a permanent version of the ugly serial-port stuff, under a compile- > time option of course, to record the lock actions. the above tool eliminates the need for this, it sucks the buffer via /dev/kmem. --- > 3. Consider redesigning the lock implementation for the purpose, rather > that try to modify the rather special lock we have now... eventually we will diverge in many different locks/primatives for specific purposes. my proposal is just for the 1st step on that path. I envision each of the 3 classes I mentioned to develop their own unique form. I do think the modified version I outlined should serve well as a start, but I am also open to suggestions for alternate algorithms. thanx for the input, lets get some more discussion of this so I can get started with the code! -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD
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