Skip site navigation (1) Skip section navigation (2)

Re: [HACKERS] Re: [PATCHES] S_LOCK reduced contention through backoff patch

From: dg(at)illustra(dot)com (David Gould)
To: ocie(at)paracel(dot)com
Cc: scrappy(at)hub(dot)org, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Re: [PATCHES] S_LOCK reduced contention through backoff patch
Date: 1998-04-30 06:32:31
Message-ID: 9804300632.AA24420@hawk.illustra.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Ocie: 
> David Gould wrote:
> 
> [snip]
> > Here is the Spinlock back off patch I promised. This does semi-random
> > backoff using select() to lessen throughput degradation due to spinlock
> > contention with large numbers of runnable backends.
> 
> Does this actually use some sort of random number generator?  I'm

No. Have a look at the patch.

> thinking that this may not be entirely necessary.  With Ethernet, this
> is needed to avoid another colission, but with locks, one process is
> guaranteed to get a lock.

In the case where this comes into play, one process already has the lock.
We have already collided. We are trying to limit the number of additional
collisions.

-dg


David Gould            dg(at)illustra(dot)com           510.628.3783 or 510.305.9468 
Informix Software  (No, really)         300 Lakeside Drive  Oakland, CA 94612
"(Windows NT) version 5.0 will build on a proven system architecture
 and incorporate tens of thousands of bug fixes from version 4.0."
                 -- <http://www.microsoft.com/y2k.asp?A=7&B=5>

In response to

pgsql-hackers by date

Next:From: Sbragion DenisDate: 1998-04-30 06:38:36
Subject: Re: [INTERFACES] Access'97 and ODBC
Previous:From: Maurice GittensDate: 1998-04-30 06:32:16
Subject: Re: [HACKERS] removing the exec() from doexec()

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group