Re: [PATCH 2/5] hashmap: allow memihash computation to be continued
From: Junio C Hamano <hidden>
Date: 2017-02-20 20:27:51
Johannes Schindelin [off-list ref] writes:
quoted
If an extra call level really matters, its "inline" equivalent in the header would probably be good.Well, the hashing is supposed to be as fast as possible, so I would like to avoid that extra call level. However, the end result is not so pretty because FNV32_BASE needs to be made public (OTOH it removes more lines than it adds):
I think our usual answer is "can we measure the difference to
demonstrate that the overhead for an extra call matter?"
As two functions sit next to each other in a single file, the code
duplication does not bother me _that_ much. A single liner
/* keep implementations of these two in sync */
in front of these two functions would not hurt, but whoever attempts
to come up with a better hash needs to stare at this file carefully
anyway, so lack of such carefulness probably wouldn't be too big an
issue, either.
But the above 8 lines are something we need to worry about after we
definitely know that we MUST have two independent functions that are
supposed to be kept in sync; a patch that makes us worry them before
we know is a premature optimization, and that bothers me even more
than the actual code duplication that can drift apart.