ktrace and KTR_DROP

Dan Nelson dnelson at allantgroup.com
Mon Jul 4 17:02:40 GMT 2005

In the last episode (Jul 03), Peter Edwards said:
> On 7/1/05, Robert Watson <rwatson at freebsd.org> wrote:
> > There are two cases where I really run into problems with the
> > current model:
> > 
> > (1) When I'm interacting with a slow file system, such as NFS over
> >      100mbps, I will always lose records, because it doesn't take
> >      long for the process to get quite ahead of the write-behind.
> It doesn't even need NFS: syscall throughput is much better than I/O
> throughput :-)

BTW, I often see dropped records even when tracing to md-backed /tmp.
Raising kern.ktrace.request_pool from 100 to 1000 helps but does not
eliminate drops.

	Dan Nelson
	dnelson at allantgroup.com

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