| From: | Neil Conway <neilc(at)samurai(dot)com> |
|---|---|
| To: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: lwlocks and starvation |
| Date: | 2004-12-02 04:55:43 |
| Message-ID: | 1101963343.22124.190.camel@localhost.localdomain |
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| Lists: | pgsql-hackers |
On Wed, 2004-12-01 at 21:51 -0500, Bruce Momjian wrote:
> Neil, where are we on this? Should we add comments? Add a TODO? A patch?
I'm not sure what the right resolution is. As I said, I don't think it's
wise to apply a patch that could have a significant impact on
performance without (a) testing its performance effect and/or (b) having
any evidence that the problem it addresses actually effects anyone in
the real world. I'll try to run some benchmarks when I get a chance.
I wrote up most of a patch to implement the "wake up all shared wakers
on LWLockRelease()" behavior to see how that would change performance,
but the patch has a subtle bug in it that I can't seem to find (I've
attached it -- comments welcome).
Certainly if we decide to leave things as they are I think we ought to
document why the behavior is intentional, but I don't think we have
enough data to make that decision yet.
-Neil
| Attachment | Content-Type | Size |
|---|---|---|
| lwlock_shared_wakeup-3.patch | text/x-patch | 2.9 KB |
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