Subject: Re: some performance diff with getc()/putc() between FreeBSD and
To: NetBSD-current Discussion List <current-users@NetBSD.ORG>
From: Stephan Uphoff <>
List: current-users
Date: 05/07/2003 14:20:26
Greg A. Woods wrote:
> Over the past week I've been running various benchmarks and other tests
> on a system destined to become a new file server 
> [...]
> So far so good w.r.t. STDIO (though the rewrite speed is astoundingly
> low on NetBSD for unknown reasons)

My guess is that the system switches too often between
reading the blocks and flushing out dirty pages to have free blocks.

Can you try to set uvmexp.freetarg to a higher number ?
Perhaps from the default 85 to 256 ?
( uvmpd_tune() in file uvm_pdaemons.c )
Don't choose the value too high, since it is not fun to watch
thousands of requests hitting a list-based disksort.

Maybe uvm needs an inactive-laundry list inserted between
the current inactive list and the free list ?
( Pages in the inactive-laundry being either clean or in the process
of being cleaned)