Date: Sat, 07 Mar 1998 23:48:52 -0800 From: Mike Smith <mike@smith.net.au> To: Julian Elischer <julian@whistle.com> Cc: Marc Slemko <marcs@znep.com>, Mike Smith <mike@smith.net.au>, hackers@FreeBSD.ORG Subject: Re: kernel wishlist for web server performance Message-ID: <199803080748.XAA09061@dingo.cdrom.com> In-Reply-To: Your message of "Sat, 07 Mar 1998 23:16:43 PST." <Pine.BSF.3.95.980307231219.16777G-100000@current1.whistle.com>
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> I would like to add here that in FreeBSD's unified VM/Buffer cache, > a mmapped file IS the buffer cache > so that a send() from an mmapped file IS copying direct fromt he buffer > cache. Ther eis ONE copy.. that from the buffer cache, into the mbuf. > > (assuming that the data got into the memory via DMA in the first place..) > you may need to have a subprocess go through and tuch all the pages to > get them into ram first.. The copyin will do this. This is why I couldn't see a real performance benefit outside of the convenience factor, and the mbuf shuffling alluded to. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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