system call performance 4.x vs 5.x [and UP vs MP]

[Don Bowman]

> From: Robert Watson [mailto:rwatson at freebsd.org]
> On Wed, 28 Jan 2004, Don Bowman wrote:
> 
 ...

> 
> BTW, is your table below "4.7 UP vs 5.x MP"?  I was left 
> unclear from the
> title.  Generally, the results I see suggest 5.x UP is 
> currently slower
> than 4.x UP (something we should make back up over the next 
> three or four
> months), but that 5.x MP is quite a bit faster than 4.x MP in many
> interesting cases (i.e., network throughput, builds, etc).  Especially
> with the recent IPI changes and scheduling changes, I see 
> substantially
> lower latency in scheduling various kernel threads on 5.x-MP 
> compared to
> 4.x-MP, which means a lot more work gets done. 

Sorry, its MP versus MP, both on the same box. [i shouldn't
have included the UP vs MP in the title, it confuses things,
it was just an observation on 4.7 in isolation].

Thank you for the excellent answer. I will try the 
pipe() suggestion, and the netperf_socket branch.

We are definitely seeing that e.g. bridging performance on 5.2 (MP)
is very much worse than on 4.7 (MP).

--don