Re: 7.1 vs. 7.2 on AIX 5L

From: Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>
To: ZeugswetterA(at)spardat(dot)at
Cc: tgl(at)sss(dot)pgh(dot)pa(dot)us, pgsql-hackers(at)postgresql(dot)org
Subject: Re: 7.1 vs. 7.2 on AIX 5L
Date: 2002-01-15 13:11:04
Message-ID: 20020115221104S.t-ishii@sra.co.jp
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> > On my machine the various implemtations have the following runtimes:
> > (with a modified s_lock test that does not sleep, and
> > SPINS_PER_DELAY 100000)
> >
> > with LinuxPPC asm: 1m5.16s (Which may not work relyably on SMP)
> > with cs: 1m12.25s
> > with fetch_and_or: 1m26.71s
>
> Aah, there we have it. Same test on a slower 4Way SMP:
>
> with LinuxPPC asm: 2m9.340s
> with cs: 10m11.15s
> with fetch_and_or: 3m55.19s
>
> These numbers look more alarming.
> Unfortunately the man page for fetch_and_or does not mention anything
> about using it as a locking primitive. It is documented atomic though,
> so I guess that is enough.
>
> Andreas
>

I did several times of pgbenhc -c 10 -t 20 with the modification you
suggested and once got a hung (all backends sleeping with the status
showing "COMMIT"). Also I had an eror:

NOTICE: LockRelease: no such lock

I'm afraid now the locking is broken. Will look into more.
--
Tatsuo Ishii

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