Messages in this thread | | | Date | Wed, 14 Sep 2005 17:35:55 -0400 | From | Peter Staubach <> | Subject | Re: [PATCH] reorder struct files_struct |
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Eric Dumazet wrote:
> Hi > > Browsing (and using) the excellent RCU infrastructure for files that > was adopted for 2.6.14-rc1, I noticed that the file_lock spinlock sit > close to mostly read fields of 'struct files_struct' > > In SMP (and NUMA) environnements, each time a thread wants to open or > close a file, it has to acquire the spinlock, thus invalidating the > cache line containing this spinlock on other CPUS. So other threads > doing read()/write()/... calls that use RCU to access the file table > are going to ask further memory (possibly NUMA) transactions to read > again this memory line. > > Please consider applying this patch. It moves the spinlock to another > cache line, so that concurrent threads can share the cache line > containing 'count' and 'fdt' fields.
How was the performance impact of this change measured?
Thanx...
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