Date: Mon, 21 Oct 2002 18:11:10 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: Kirk McKusick <mckusick@FreeBSD.org> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/specfs spec_vnops.c src/sys/kern subr_disk.c src/sys/ufs/ffs ffs_snapshot.c Message-ID: <Pine.BSF.4.21.0210211807240.24506-100000@InterJet.elischer.org> In-Reply-To: <200210220059.g9M0xnWm049023@repoman.freebsd.org>
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On Mon, 21 Oct 2002, Kirk McKusick wrote: > mckusick 2002/10/21 17:59:49 PDT > > On the issue of scaling HZ, I believe that the current scheme is > better than using a fixed quantum of time. As machines and I/O > subsystems get faster, the resolution on the clock also rises. > So, ten years from now we will be slowing things down for shorter > periods of time, but the proportional effect on the system will > be about the same as it is today. So, I view this as a feature > rather than a drawback. Hence this patch sticks with using HZ. Rather than using a time delay, wouldn't it be possible to ensure that requests of some types can not occur back-to-back, (i.e. the disk scheduler skips them in the queue or something) and only soes requests from that source "1 in 2" or "1 in 3" or similar. I know this would result in a hi-pro and low-pri queue for the disks but that may not be such a bad idea.. Julian To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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