Messages in this thread | | | Subject | Re: [PATCH net-next] arch_fast_hash: avoid indirect function calls and implement hash in asm | From | Hannes Frederic Sowa <> | Date | Thu, 04 Dec 2014 17:37:10 +0100 |
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On Do, 2014-12-04 at 23:56 +0800, Herbert Xu wrote: > On Thu, Dec 04, 2014 at 02:08:50PM +0100, Hannes Frederic Sowa wrote: > > By default the arch_fast_hash hashing function pointers are initialized > > to jhash(2). If during boot-up a CPU with SSE4.2 is detected they get > > updated to the CRC32 ones. This dispatching scheme incurs a function > > pointer lookup and indirect call for every hashing operation. > > Just curious, is jhash actually faster than generic C CRC32 on > common platforms?
Yes, jhash always beats crc32 in software on x86_64 and ia32.
Bye, Hannes
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