Messages in this thread | | | Date | Mon, 19 Nov 2007 19:33:25 -0800 (PST) | From | Christoph Lameter <> | Subject | Re: [rfc 00/45] [RFC] CPU ops and a rework of per cpu data handling on x86_64 |
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n Tue, 20 Nov 2007, Andi Kleen wrote:
> > > Although we have a per-cpu area base in a fixed global register > > for addressing, the above isn't beneficial on sparc64 because > > the atomic is much slower than doing a: > > > > local_irq_disable(); > > nonatomic_percpu_memory_op(); > > local_irq_enable(); > > Again might be pointing out the obvious, but you > need of course save_flags()/restore_flags(), not disable/enable(). > > If it was just disable/enable x86 could do it much faster too > and Christoph probably would never felt the need to approach > this project for his SLUB fast path.
I already have no need for that anymore with the material now in Andrews tree. However, this cuts out another 6 cycles from the fastpath and I found that the same principles reduce overhead all over the kernel.
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