Re: [this_cpu_xx V6 7/7] this_cpu: slub aggressive use of this_cpuoperations in the hotpaths

[David Rientjes]

On Tue, 13 Oct 2009, Christoph Lameter wrote:

> > For an optimized fastpath, I'd expect such a workload would result in at
> > least a slightly higher transfer rate.
> 
> There will be no improvements if the load is dominated by the
> instructions in the network layer or caching issues. None of that is
> changed by the path. It only reduces the cycle count in the fastpath.
> 

Right, but CONFIG_SLAB shows a 5-6% improvement over CONFIG_SLUB in the 
same workload so it shows that the slab allocator does have an impact in 
transfer rate.  I understand that the performance gain with this patchset, 
however, may not be representative with the benchmark since it also 
frequently uses the slowpath for kmalloc-256 about 25% of the time and the 
added code of the irqless patch may mask the fastpath gain.
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