Date: Wed, 28 Jan 2004 12:43:10 -0500 From: John Baldwin <jhb@FreeBSD.org> To: Peter Losher <Peter_Losher@isc.org> Cc: current@freebsd.org Subject: Re: spin lock panic in 5.2-REL Message-ID: <200401281243.10655.jhb@FreeBSD.org> In-Reply-To: <200401271420.05240.Peter_Losher@isc.org> References: <20040127082106.L14045@farside.isc.org> <200401271334.07761.jhb@FreeBSD.org> <200401271420.05240.Peter_Losher@isc.org>
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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@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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