Re: Errors in the VM - detailed (or is it Tux? or rmap? or those together...)

From: Roy Sigurd Karlsbakk (roy@karlsbakk.net)
Date: Sat Feb 02 2002 - 11:39:22 EST

> How do you know that it gets into this at RAMx2? Have you added 'bi' from
> vmstat?

yes

> One interesting thing to notice from vmstat is...
>
> r b w swpd free buff cache si so bi bo in cs us sy id
> When performing nicely:
> 0 200 1 1676 3200 3012 786004 0 292 42034 298 791 745 4 29 67
> 0 200 1 1676 3308 3136 785760 0 0 44304 0 748 758 3 15 82
> 0 200 1 1676 3296 3232 785676 0 0 44236 0 756 710 2 23 75
> Later when being slow:
> 0 200 0 3468 3316 4060 784668 0 0 1018 0 613 631 1 2 97
> 0 200 0 3468 3292 4060 784688 0 0 1034 0 617 638 0 3 97
> 0 200 0 3468 3200 4068 784772 0 0 1066 6 694 727 2 4 94
>
> No swap activity (si + so == 0), mostly idle (id > 90).
> So it is waiting - on what??? timer? disk?

I don't know. All I know is that with rmap-11c, it works

> Roy, did you notice the mail from Andrew Morton:
> > heh. Yep, Roger finally nailed it, I think.
> >
> > Roy says the bug was fixed in rmap11c. Changelog says:
> >
> >
> > rmap 11c:
> > ...
> > - elevator improvement (Andrew Morton)
> >
> > Which includes:
> >
> > - queue_nr_requests = 64;
> > - if (total_ram > MB(32))
> > - queue_nr_requests = 128;
> > + queue_nr_requests = (total_ram >> 9) &
> > ~15; /* One per half-megabyte */
> > + if (queue_nr_requests < 32)
> > + queue_nr_requests = 32;
> > + if (queue_nr_requests > 1024)
> > + queue_nr_requests = 1024;
>
> rmap11c changed the queue_nr_requests, that problem went away.
> But another one showed its ugly head...
>
> Could you please try this part of rmap11c only? Or the very simple one
> setting queue_nr_request to = 2048 for a test drive...

u mean - on a 2.4.1[18](-pre.)? kernel?

I'll try 

--
Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA

Computers are like air conditioners.
They stop working when you open Windows.

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This archive was generated by hypermail 2b29 : Thu Feb 07 2002 - 21:00:23 EST