Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH v2] ice: use min_t() to make code cleaner in ice_gnss | Date | Tue, 22 Mar 2022 22:27:58 +0000 |
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From: Jakub Kicinski > Sent: 22 March 2022 18:28 > > On Tue, 22 Mar 2022 18:12:08 +0000 David Laight wrote: > > > > Oh FFS why is that u16? > > > > Don't do arithmetic on anything smaller than 'int' > > > > > > Any reasoning? I don't say it's good or bad, just want to hear your > > > arguments (disasms, perf and object code measurements) etc. > > > > Look at the object code on anything except x86. > > The compiler has to add instruction to mask the value > > (which is in a full sized register) down to 16 bits > > after every arithmetic operation. > > Isn't it also slower on some modern x86 CPUs? > I could have sworn someone mentioned that in the past.
Not in the cpu clock count tables I've read.
David
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