Re: Performance Results for Ingo's O(1)-scheduler

[Rusty Russell <rusty@rustcorp.com.au>]

On Mon, 21 Jan 2002 20:16:28 -0800
Ryan Cumming <bodnar42@phalynx.dhs.org> wrote:

> On January 21, 2002 19:55, Adam Keys wrote:
> > I'm curious about the performance of the 4-way and 8-way systems.  I know
> > nothing about this benchmark.  IIRC correctly it simulates chat clients
> > connecting to a server and talking to each other.  Is it a CPU, memory, or
> > disk bound benchmark?  What is causing the 4-way machines to be only 2x the
> > performance of the 1-way machine and the 8-way machines to be < 3x the
> > performance?  Is the system bus the limiting factor on those machines?
> 
> Memory bus, lock contention, syncronization issues. SMP really isn't as 
> magical as people think after the overhead is taken in to account.

Volcanomark is a Java(TM) chatroom benchmark: multiple rooms, where for each
room, every input from a client generates a write to every other client
(think broadcast storm).

chat (which is a C version of Volcanomark) is useful for testing, as is
hackbench2 (which is cut down to just exhibit the runqueue problem, and
doesn't even use threads).

Hope that helps,
Rusty.
-- 
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.