Messages in this thread | | | Date | Sat, 10 Aug 2002 10:46:30 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [patch 6/12] hold atomic kmaps across generic_file_read |
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On Sat, 10 Aug 2002, Jamie Lokier wrote: > > This will only provide the performance benefic when `aligned_malloc' > return "fresh" memory, i.e. memory that has never been written to.
Absolutely.
Think o fthe optimization as a way to give application writers a new way of being efficient.
In particular, I remember when the gcc people were worried about the most efficient way to read in a file for preprocessing (Neil Booth, mainly). Neil did all these timings on where the cut-off point was for using mmap vs just using read().
For people like that, wouldn't it be nice to just be able to tell them: if you do X, we guarantee that you'll get optimal zero-copy performance for reading a file.
> But it's a nice way to optimise if you are _deliberately_ optimising a > user space program.
Exactly.
Linus
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