Date: Mon, 4 Jul 2005 12:02:39 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Peter Edwards <peadar.edwards@gmail.com> Cc: Peter Edwards <peadar@freebsd.org>, arch@freebsd.org, Robert Watson <rwatson@freebsd.org> Subject: Re: ktrace and KTR_DROP Message-ID: <20050704170239.GQ2392@dan.emsphone.com> In-Reply-To: <34cb7c8405070311131cd1ca8a@mail.gmail.com> References: <20050701132104.GA95135@freefall.freebsd.org> <20050701155757.A36905@fledge.watson.org> <34cb7c8405070311131cd1ca8a@mail.gmail.com>
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In the last episode (Jul 03), Peter Edwards said: > On 7/1/05, Robert Watson <rwatson@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@allantgroup.com
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