Re: Patch to improve reliability of postgresql on linux nfs

On Tue, Sep 13, 2011 at 03:02:57PM +0200, Florian Pflug wrote:
> On Sep13, 2011, at 14:58 , ktm@rice.edu wrote:
> > It will be interesting to see if there are any performance ramifications to
> > this new write function.
> 
> What would those be? For non-interruptible reads and writes, the overhead
> comes down to an additional function call (if we don't make pg_write_nointr
> inlined) and a few conditional jumps (which branch prediction should be
> able to take care of). These are bound to disappear in the noise compared
> to the cost of the actual syscall.
> 
> best regards,
> Florian Pflug
> 
That would be my expectation too. It is just always nice to benchmark changes,
just in case. I have had similar simple changes blow out a cache and have a
much greater impact on performance than might be expected from inspection. :)

Regards,
Ken