Subject: Re: Faster pipes, now with uvm_loan()
To: =?iso-8859-1?Q?Jarom=EDr_Dolecek?= <jdolecek@netbsd.org>
From: Frank van der Linden <fvdl@wasabisystems.com>
List: tech-kern
Date: 04/10/2001 16:50:34
On Tue, Apr 10, 2001 at 04:23:21PM +0200, Jaromír Dolecek wrote:
> How big has the Pentium cache?

The P54C had 8k L1 icache and dcache, external depended on the motherboard.
This one has 256k or 512k, I'd have to open the case to check. I suspect
it's 256k.

> if hbench doing differently to lmbench to give such wildly different
> comparison. You might try how the results would be without
> uvm_loan(), if you add a define PIPE_NODIRECT.

I defined it, and now get:

bw_pipe:
   4k: 27.222467 (std. 0.162706, 0.60%) [median 27.213850]
   8k: 25.718017 (std. 0.555617, 2.16%) [median 25.999500]
   16k: 26.829900 (std. 0.150212, 0.56%) [median 26.828550]
   32k: 28.408767 (std. 0.082694, 0.29%) [median 28.436200]
   64k: 26.832150 (std. 0.698198, 2.60%) [median 26.768150]
   128k: 25.776267 (std. 0.315786, 1.23%) [median 25.718000]
   256k: 25.391000 (std. 0.166197, 0.65%) [median 25.371300]
   512k: 24.342383 (std. 0.365178, 1.50%) [median 24.400800]
   1m: 23.778667 (std. 0.111437, 0.47%) [median 23.764850]
   2m: 23.293367 (std. 0.291396, 1.25%) [median 23.260300]
   4m: 22.598550 (std. 0.127091, 0.56%) [median 22.612850]

These numbers are about the same for 4k sizes, and for > 64k
sizes.  So the loan code is certainly doing it's job for 4-64k.

- Frank

-- 
Frank van der Linden                           fvdl@wasabisystems.com
======================================================================
Quality NetBSD CDs, Support & Service.   http://www.wasabisystems.com/