Re: profiling connection overhead - Mailing list pgsql-hackers

From Tom Lane
Subject Re: profiling connection overhead
Date
Msg-id 18594.1290612342@sss.pgh.pa.us
Whole thread Raw
In response to Re: profiling connection overhead  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: profiling connection overhead
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Nov 24, 2010 at 2:10 AM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com> wrote:
>> Micro-optimizing that search for the non-zero value helps a little bit
>> (attached). Reduces the percentage shown by oprofile from about 16% to 12%
>> on my laptop.

That "micro-optimization" looks to me like your compiler leaves
something to be desired.

> The first optimization that occurred to me was "remove the loop
> altogether".

Or make it execute only in assert-enabled mode, perhaps.

This check had some use back in the bad old days, but the ResourceOwner
mechanism has probably removed a lot of the argument for it.

The counter-argument might be that failing to remove a buffer pin would
be disastrous; but I can't see that it'd be worse than failing to remove
an LWLock, and we have no belt-and-suspenders-too loop for those.
        regards, tom lane


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