Jes Sorensen wrote: > Zhang, Xiantao wrote: >>> From 697d50286088e98da5ac8653c80aaa96c81abf87 Mon Sep 17 00:00:00 >>> 2001 >> From: Xiantao Zhang <[EMAIL PROTECTED]> >> Date: Mon, 31 Mar 2008 09:50:24 +0800 >> Subject: [PATCH] KVM:IA64: Implement smp_call_function_mask for ia64 >> >> This function provides more flexible interface for smp >> infrastructure. Signed-off-by: Xiantao Zhang >> <[EMAIL PROTECTED]> > > Hi Xiantao, > > I'm a little wary of the performance impact of this change. Doing a > cpumask compare on all smp_call_function calls seems a little > expensive. Maybe it's just noise in the big picture compared to the > actual cost of the IPIs, but I thought I'd bring it up. > Keep in mind that a cpumask can be fairly big these days, max NR_CPUS > is currently 4096. For those booting a kernel with NR_CPUS at 4096 on > a dual CPU machine, it would be a bit expensive. > > Why not keep smp_call_function() the way it was before, rather than > implementing it via the call to smp_call_function_mask()?
Hi, Jes I'm not aware of the performance impact before. If the worst case occurs, it need 64 comparisions ? Maybe keeping old smp_call_function is better ? Xiantao > > ------------------------------------------------------------------------ - > Check out the new SourceForge.net Marketplace. > It's the best place to buy or sell services for > just about anything Open Source. > http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketp lace > _______________________________________________ > kvm-devel mailing list > kvm-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/kvm-devel ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
