From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
---|---|
To: | Tatsuo Ishii <ishii(at)postgresql(dot)org> |
Cc: | robertmhaas(at)gmail(dot)com, pgsql-hackers(at)postgresql(dot)org, manabu(dot)ori(at)gmailc(dot)com |
Subject: | Re: spinlocks on HP-UX |
Date: | 2011-12-28 20:18:36 |
Message-ID: | 4EFB799C.9080303@enterprisedb.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 28.12.2011 14:03, Tatsuo Ishii wrote:
>>> With help from IBM Japan Ltd. we did some tests on a larger IBM
>>> machine than Tom Lane has used for his
>>> test(http://archives.postgresql.org/message-id/8292.1314641721@sss.pgh.pa.us).
>>> In his case it was IBM 8406-71Y, which has 8 physical cores and
>>> 4SMT(32 threadings). Ours is IBM Power 750 Express, which has 32
>>> physical cores and 4SMT(128 threadings), 256GB RAM.
>>>
>>> The test method was same as the one in the article above. The
>>> differences are OS(RHEL 6.1), gcc version (4.4.5) and shared buffer
>>> size(8GB).
>>>
>>> We tested 3 methods to enhance spin lock contention:
>>>
>>> 1) Add "hint" parameter to lwarx op which is usable POWER6 or later
>>> architecure.
>>>
>>> 2) Add non-locked test in TAS()
>>>
>>> 3) #1 + #2
>>>
>>> We saw small performance enhancement with #1, larger one with #2 and
>>> even better with #1+#2.
>>
>> Hmm, so you added the non-locked test in TAS()? Did you try adding it
>> just to TAS_SPIN()? On Itanium, I found that it was slightly better
>> to do it only in TAS_SPIN() - i.e. in the contended case.
>
> Here is new patch using TAS_SPIN(), created by Manabu Ori from IBM
> Japan. Also this patch deal with older Power architectures which do
> not have "hint" argument of lwarx opcode.
>
> According to him, the patch resulted in much better performance stock
> git head.
Impressive results.
config/c-compiler.m4 doesn't seem like the right place for the configure
test. Would there be any harm in setting the lwarx hint always; what
would happen on older ppc processors that don't support it?
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
From | Date | Subject | |
---|---|---|---|
Next Message | Tatsuo Ishii | 2011-12-28 22:27:57 | Re: spinlocks on HP-UX |
Previous Message | Tom Lane | 2011-12-28 19:35:34 | Re: age(xid) on hot standby |