Messages in this thread | | | Date | Thu, 28 Apr 2022 16:11:45 +0100 | Subject | Re: [PATCH net-next 02/11] udp/ipv6: refactor udpv6_sendmsg udplite checks | From | Pavel Begunkov <> |
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On 4/28/22 15:09, Paolo Abeni wrote: > On Thu, 2022-04-28 at 11:56 +0100, Pavel Begunkov wrote: >> Don't save a IS_UDPLITE() result in advance but do when it's really >> needed, so it doesn't store/load it from the stack. Same for resolving >> the getfrag callback pointer. > > It's quite unclear to me if this change brings really any performance > benefit. The end results will depend a lot on the optimization > performed by the compiler, and IMHO the code looks better before this > modifications.
There is a lot of code and function calls between IS_UDPLITE() and use sites, because of alias analysis the compiler will be forced to call it early in the function and store something on stack. I don't believe it will be able to keep in a register. But it's not a problem to drop it
-- Pavel Begunkov
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