Re: [PATCH] 2.5.21 IDE 91

[Jens Axboe <axboe@suse.de>]

On Sat, Jun 15 2002, rwhron@earthlink.net wrote:
> > One possibile culprit here is the doubling of the request queue size
> > in 2.5.20.  A long time ago it was 1024 slots.  Then it went to
> > 128.  That's where it is in Marcelo kernels.  Then -ac kernels
> > went up to 1024 because they have read-latency2.  Somehow 2.5 found
> > itself at 256 slots.  In 2.5.20 it slealthily snuck up to 512
> > slots.  I didn't squeak about this because I was interested to see what
> > effect it would have.
> 
> Interesting.  I've seen read-latency2 drop dbench throughput in -aa
> kernels (but I use it anyway).  I'd like to capture the request
> queue size.  Is there a command or file in /proc that displays 
> it, or should I just grep drivers/block/ll_rw_blk.c?

There is currently no way you can capture the queue request state. In
the past I've done sysrq hacks to display it, but that's about it.

-- 
Jens Axboe