Date: Fri, 18 Apr 1997 18:09:27 +0900 From: KATO Takenori <kato@eclogite.eps.nagoya-u.ac.jp> To: rb@gid.co.uk Cc: kato@eclogite.eps.nagoya-u.ac.jp, freebsd-bugs@freefall.freebsd.org Subject: Re: kern/3292: Cyrix 486 performance problem Message-ID: <199704180909.SAA04619@gneiss.eps.nagoya-u.ac.jp> In-Reply-To: Your message of "Fri, 18 Apr 1997 08:56:33 %2B0100" References: <l03020901af7cd2bf56c0@[194.32.164.2]>
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From: Bob Bishop <rb@gid.co.uk> Subject: Re: kern/3292: Cyrix 486 performance problem Date: Fri, 18 Apr 1997 08:56:33 +0100 > b) It runs DOS but slow - BIOS doesn't know how to initialise the chip. > AFAIK DOS contains no Cyrix-specific initialisation code. DOS contains no Cyrix code, but there are device drivers to enable CPU cache and provide cache control. FreeBSD doesn't contain cache control in IBM-PC code (FreeBSD contains cache control in PC-98 code). > BUT in any case, I think the cache should be enabled by default. If that > means implementing cache flush code, so be it. If we need to change only DMA code in isa.c, it is VERY easy. What we should do is: 1. Enable CPU cache by default. 2. Copy cache control code from PC-98 tree into IBM-PC tree. In PC-98 tree, that is, `PC98' is defined, when Cyrix 486 or 5x86 is detected, set need_post_dma_flush or need_pre_dma_flush as 1. The DMA access routines (pc98.c and bs driver) check these variable and execute wbinvd() or invd(). ---- KATO Takenori <kato@eclogite.eps.nagoya-u.ac.jp> Dept. Earth Planet. Sci., Nagoya Univ., Nagoya, 464-01, Japan PGP public key: finger kato@eclogite.eps.nagoya-u.ac.jp ------------------- Powered by FreeBSD(98) -------------------
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