VM/IO performance sucks in 2.3.99-pre6

From: Richard Gooch (rgooch@ras.ucalgary.ca)
Date: Wed May 03 2000 - 11:34:13 EST

  Hi, all. I know there's been grumbling about VM/IO/LRU's/page aging
recently. To give an idea of how bad it is:

I have a drive that is capable of delivering >12 MB/s. By using dd on
the block device (reading in more data than I have RAM), I quickly get
to a state where I'm getting << 1 MB/s. My guess is that I'm getting
100 kB/s or less. Once this happens, it seems easiest to reboot to
bring things back to a sane state.

It seems the current LRU algorithm is "Least Recently Used pages will
remain in RAM the longest". I'd call that a BFULRU.


Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca

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