Messages in this thread | | | Date | Fri, 16 Jan 2009 11:12:00 +1100 | From | Herbert Xu <> | Subject | Re: [PATCH] percpu: add optimized generic percpu accessors |
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Ingo Molnar <mingo@elte.hu> wrote: > >> Of course. But do any architectures actually _need_ that for a single >> read? > > not for a read i guess - but for the other ops like add/and/or/xor.
One of the things I'd like to see happen with this work is for us to have a cheap per-cpu atomic counter that we can use for SNMP stats.
If we can make the inc/add variants into a single instruction, then it won't need to disable preemption or interrupts.
So if you could design the API such that we have a variant of add/inc that automatically disables/enables preemption then we can optimise that away on x86.
Thanks, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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