Date: Wed, 24 Dec 2003 11:12:02 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Alfred Perlstein <alfred@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern subr_smp.c Message-ID: <XFMail.20031224111202.jhb@FreeBSD.org> In-Reply-To: <20031224001758.GT60229@elvis.mu.org>
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On 24-Dec-2003 Alfred Perlstein wrote: > * John Baldwin <jhb@FreeBSD.org> [031223 09:04] wrote: >> >> On 23-Dec-2003 Alfred Perlstein wrote: >> > alfred 2003/12/23 05:54:16 PST >> > >> > FreeBSD src repository >> > >> > Modified files: >> > sys/kern subr_smp.c >> > Log: >> > Introduce mp_maxcpus which can be used by libkvm utils to find out >> > how many CPUs the system was compiled for. >> > Export the variable via a sysctl node 'kern.smp.maxcpus' as well. >> >> Why does libkvm care about more than mp_maxid? > > See mbuf.c from netstat(1). basically some arrays in the kernel > are based on MAXCPU so it has to know how much to copy. It only needs to copy up to mp_maxid though. All the rest after that are just garbage anyways and you merely waste time by copying that. I guess if you have a structure containing multiple arrays then that would need maxcpu. If the arrays are standalone you don't need it though. -- 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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