Date: Mon, 25 Jan 1999 16:59:40 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Sheldon Hearn <axl@iafrica.com> Cc: Brian Feldman <green@unixhelp.org>, Lee Cremeans <lee@st-lcremean.tidalwave.net>, current@FreeBSD.ORG Subject: Re: IDE DMA works, I'll be a... Message-ID: <199901260059.QAA08899@apollo.backplane.com> References: <1624.917311532@axl.noc.iafrica.com>
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:On Mon, 25 Jan 1999 19:40:38 EST, Brian Feldman wrote:
:
:> I say this because I am down to ~2.5MB/s on each hard drive, a MB or
:> so decrease; I also seem to be reading (bs=512k) from the CD uncooked
:...
:
:Since I rebuilt world shortly after Matt's VM surgery started, I've also
:noticed this -- lower apparent transfer rates from /dev/zero to disk,
:higher CPU usage during such transfers.
:
:I'm _not_ saying it's Matt's stuff that's done this, it's just that that
:was the stuff I _noticed_ happening in commit mail. I think I saw
:something happening to wd.c recently as well, so I _definitely_ am not
:going on record as laying blame.
:
:Just some confirmation. :-)
:
:Ciao,
:Sheldon.
Hmm, interesting. A dd copy doesn't touch on the main of what I did,
but I do have a (bad) hack in there to handle a case that John brought
up in regards to the inactive page queue getting overloaded with
clean meta-data. It might be interesting to turn that off and see if
your transfer rates improve.
You can turn off the hack by commenting out the case that activates
it: Add the #if/#endif and split the open brace out from the else,
as shown.
I would like to know if your transfer rate improves or not, and by
how much.
/*
* Figure out what to do with dirty pages when they are encountered.
* Assume that 1/3 of the pages on the inactive list are clean. If
* we think we can reach our target, disable laundering (do not
* clean any dirty pages). If we miss the target we will loop back
* up and do a laundering run.
*/
#if 0
if (cnt.v_inactive_count / 3 > page_shortage) {
maxlaunder = 0;
launder_loop = 0;
} else
#endif
{
maxlaunder =
(cnt.v_inactive_target > max_page_launder) ?
max_page_launder : cnt.v_inactive_target;
launder_loop = 1;
}
-Matt
Matthew Dillon
<dillon@backplane.com>
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