Subject: Re: SS20 network performance
To: None <port-sparc@netbsd.org>
From: Martin Husemann <martin@duskware.de>
List: port-sparc
Date: 05/17/2002 13:22:43
> Now, the maximum throughput I've been able to achieve, is 2.57MB/s,
> measured using wget
..
> This is strange, because I've reached over 7 MB/s throughputs with
> Solaris 8 running ipfilter on the very same platform.

So this is interesting. 2.57MB/s is not bad, my LX only gets around
1.1MB/s.

Matthias Scheeler once tried to address this by bringing in a version of
the hme driver that uses pre-allocated dma maps, thereby avoiding one copy
of the data.

We then benchmarked this, and it didn't help performance on the LX (which may
be due to the crippled cache size, of course) and it *dramatically* reduced
performance on sparc64 machines (I get the expected 11MB/s on my U5 with hme).

So this driver version was backed out again, until further research would
have shown the culprit for the sparc64 performance issue (the iommu operations
are suspect) and avoided it. AFAICT this has not happened yet.

Other drivers using similar techniques (if_vr.c for example) exhibit the
same performance problems on sparc64.

Can you easily test driver patches on your SS20 to see if they improve
performance for you?

Martin