Re: [HACKERS] spin locks - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] spin locks
Date
Msg-id 199803160508.AAA22455@candle.pha.pa.us
Whole thread Raw
In response to Re: [HACKERS] spin locks  (The Hermit Hacker <scrappy@hub.org>)
Responses Re: [HACKERS] spin locks
List pgsql-hackers
>
> On Sun, 15 Feb 1998, Bruce Momjian wrote:
>
> > >     I'm not quite sure I follow this...in a multi-cpu environment,
> > > would process_yield() introduce a problem? *raised eyebrow*
> >
> > Probably.  I would leave the code as-is for multi-cpu systems.
>
>     So...how would we determine which is which? *raised eyebrow*
>
> > Yep, but we need to check for multiple cpu's first before enabling it.
> > That would be a good trick from configure.
>
>     I'm curious, still, as to whether this function would help
> performance on a multi-cpu environment as well...what if 2 processes are
> running on one of two CPUs, and another 2 on the other? *raised eyebrow*

Good point.  You would almost need to know if the one holding the lock
was currently running.  But it wouldn't be un-runnable while it was
holding the spinlock, so it should be run-able, even if it is not
currently running.

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