> I'd strongly suggest making the pipe buffers remain the
> size of 1 page and allocate them dynamically.
Is there some consensus on what the limit for a pipe
buffer should be? Unrestricted dynamic allocation
is certainly a bad idea, but I have no idea what the
maximum should be.
> This goes towards another pipe optimization that has been
> suggested: where possible, one could flip a full page into
> the reader's address space rather than copying, making
> for a substantial gain in pipe bandwidth.
Do you mean the situation, where the user buffer is page aligned
and at least one page long as "where possible"? This is probably
not a common situation in real programs (although it surely
could be a proposed optimization for programs that really
need the bandwidth).
The kernel certainly could try to have the data page-aligned -
some kind of double-buffering could arrange for this (maybe
this could also ensure that the reader and writer operate
on different data most of the time - could be interesting
for SMP).
If it was already discussed somewhere / someone works on it,
could you give some reference / keywords?
Regards
-- Stano
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