Re: [patch] epoll use a single inode ...

[Anton Blanchard]

> OK, 200 cycles...
> 
> But what is the cost of the conditional branch you added in prefetch(x) ?

Much less than the tablewalk. On ppc64 a tablewalk of an address that is
not populated in the hashtable will incur 2 cacheline lookups (primary
and secondary buckets). This plus the MMU state machine overhead adds up.

Cue Linus rant about PowerPC MMU :)

Anton
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