Re: Minor optimisation of XLogInsert()

Robert Haas <robertmhaas@gmail.com> writes:
> (I wonder if we shouldn't just align every shared memory allocation to
> 64 or 128 bytes.  It wouldn't waste much memory and it would make us
> much more resistant to performance changes caused by minor
> modifications to the shared memory layout.)

I could get behind this idea if we had a reasonably clear idea of the
hardware's cache line width, but AFAIK there is no portable way to
identify that.  (This is a pretty fatal objection to Simon's original
patch as well...)
        regards, tom lane