From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: xmm2 - monitor Linux MM active/inactive lists graphically Date: Sun, 28 Oct 2001 11:13:28 -0800 (PST) Reply-To: barryn@pobox.com In-Reply-To: <87k7xfk6zd.fsf@atlas.iskon.hr> from "Zlatko Calusic" at Oct 28, 2001 06:30:14 PM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20011028191328.CCC828A6EA@pobox.com> From: barryn@pobox.com (Barry K. Nathan) Sender: owner-linux-mm@kvack.org Return-Path: To: zlatko.calusic@iskon.hr Cc: Linus Torvalds , Jens Axboe , Marcelo Tosatti , linux-mm@kvack.org, lkml List-ID: > Unfortunately, things didn't change on my first disk (IBM 7200rpm > @home). I'm still getting low numbers, check the vmstat output at the > end of the email. > > But, now I found something interesting, other two disk which are on > the standard IDE controller work correctly (writing is at 17-22 > MB/sec). The disk which doesn't work well is on the HPT366 interface, > so that may be our culprit. Now I got the idea to check patches > retrogradely to see where it started behaving poorely. > > Also, one more thing, I'm pretty sure that under strange circumstances > (specific alignment of stars) it behaves well (with appropriate > writing speed). I just haven't yet pinpointed what needs to be done to > get to that point. I didn't read the entire thread, so this is a bit of a stab in the dark, but: This really reminds me of a problem I once had with a hard drive of mine. It would usually go at 15-20MB/sec, but sometimes (under both Linux and Windows) would slow down to maybe 350KB/sec. The slowdown, or lack thereof, did seem to depend on the alignment of the stars. I lived with it for a number of months, then started getting intermittent I/O errors as well, as if the drive had bad sectors on disk. The problem turned out to be insufficient ventilation for the controller board on the bottom of the drive -- it was in the lowest 3.5" drive bay in my case, so the bottom of the drive was snuggled next to a piece of metal with ventilation holes. The holes were rather large (maybe 0.5" diameter) -- and so were the areas without holes. Guess where one of the drive's controller chips happened to be positioned, relative to the holes? :( Moving the drive up a bit in the case, so as to allow 0.5"-1" of space for air beneath the drive, fixed the problem (both the slowdown and the I/O errors). I don't know if this is your problem, but I'm mentioning it just in case it is... -Barry K. Nathan -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/