Subject: Re: Do some disk accesses miss the UVM?
To: David Laight <david@l8s.co.uk>
From: Rafal Boni <rafal@mediaone.net>
List: tech-kern
Date: 01/23/2002 17:49:33
In message <3C4F3303.BBE8A25F@l8s.co.uk>, you write: 

-> If I do:
-> 
-> dsl@snowdrop:-ksh$ cd /usr/bsd-current
-> dsl@snowdrop:-ksh$ time find . | wc
->   109552  109552 4153470
->   166.93s real     1.81s user     1.23s system
-> dsl@snowdrop:-ksh$ time find . |wc
->   109552  109552 4153470
->   165.35s real     1.75s user     1.27s system
-> 
-> Repeating the find takes about the same length of time, the disk
-> 'rattles' throughout.  Memory use (reported by 'top') stays basically
-> constant 'Memory: 33M Act, 308K Wired, 187M Free, 1025M Swp free'.

I bet you run out of vnodes, the vnodes for stuff you've already gotten get
recycled and you have to go back to disk to fetch the necessary data.  I'm
willing to bet money on the first half, but I'm unsure why you'd need to go
to disk again anyway -- is this some fallout from metadata not being in UBC?

(I assume you're running -current)

--rafal

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Rafal Boni                                                  rafal@mediaone.net