spin lock panic in 5.2-REL

[John Baldwin]

On Tuesday 27 January 2004 05:19 pm, Peter Losher wrote:
> On Tuesday 27 January 2004 10:34 am, John Baldwin wrote:
> > This is a very hard to debug problem.  If WITNESS is on it provides more
> > useful information that can help track that down, but I wouldn't expect a
> > production machine to be using WITNESS.
>
> Yes, I was running a kernel for a short while w/ INVARIANTS and WITNESS,
> but it was basically useless after a couple of hours under load under the
> giant lock.  How much of a performance hit is just WITNESS?

A lot.  I think Robert Watson has seen as high a performance impact as 40%.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org