Date: Mon, 12 Jul 1999 10:50:45 +0200 (CEST) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-current@FreeBSD.ORG Subject: Re: "objtrm" problem probably found (was Re: Stuck in "objtrm") Message-ID: <199907120850.KAA21696@dorifer.heim3.tu-clausthal.de>
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Doug Rabson wrote in list.freebsd-current: > On Mon, 12 Jul 1999, Peter Jeremy wrote: > > That said, it should be fairly simple to change Matt's new in-line > > assembler versions to insert LOCK prefixes when building an SMP > > kernel. (Although I don't know that this is necessary yet, given > > the `Big Giant Lock'). > > We don't need the lock prefix for the current SMP implementation. A lock > prefix would be needed in a multithreaded implementation but should not be > added unless the kernel is an SMP kernel otherwise UP performance would > suffer. In my list of i386 clock cycles, the lock prefix is listed with 0 (zero) cycles. That would mean that it does not affect performance on UP systems (except that it bloats the kernel by 1 byte for each such macro, which _might_ have negative effect on the caches in the worst case, but this is not very likely). Regards Oliver -- Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de) "In jedem Stück Kohle wartet ein Diamant auf seine Geburt" (Terry Pratchett) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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