Subject: Re: rpc xid randomness
To: Jun-ichiro itojun Hagino <itojun@itojun.org>
From: Brett Lymn <blymn@baesystems.com.au>
List: tech-userlevel
Date: 09/09/2003 12:17:15
On Tue, Sep 09, 2003 at 10:51:59AM +0900, Jun-ichiro itojun Hagino wrote:
>
> could anyone with lmbench do lat_rpc with the old code?
>
I cannot seem to reliably get lat_rpc to run - sometimes I get rpc
timeouts but the couple of times it has worked I get 61 microseconds
for RPC/tcp and 57 microseconds for RPC/udp... or numbers around that
mark. This is running on a laptop with a 1Ghz PIII, 256Mb RAM - I was
running X at the time I ran the benchmark.
> the numbers i've posted (hoge.c) could be misleading, as (1) it only
> measures the algorithm itself, not the impact to RPC code as a
> whole,
True - that is why I was careful not to overreact to your timings.
Can you post the results of lat_rpc for comparison?
> (2) it runs on userland so kernel-userland overhead like gettimeofday()
> call which makes it inaccurate.
>
True but that overhead is relatively constant in your before/after
case so the perturbation in your measurement should not be that high,
certainly not by 3 orders of magnitude which is what your numbers were
indicating.
--
Brett Lymn