Thread: Does "HYPERTHREADING" do any harm if we use with RH9.0 and postgresql?

Does "HYPERTHREADING" do any harm if we use with RH9.0 and postgresql?

From
amrit@health2.moph.go.th
Date:
I use RH 9.0 with postgresql 7.3.2 and 4 Gb ram  [server spec. Dual Xeon 3.0]
and someone mention that the hyperthreading will not help but if I let it there
will it be any harm to the system?
Any comment please.
Amrit
Thailand


Re: Does "HYPERTHREADING" do any harm if we use with RH9.0 and postgresql?

From
Josh Berkus
Date:
Amrit,

> I use RH 9.0 with postgresql 7.3.2 and 4 Gb ram  [server spec. Dual Xeon
> 3.0] and someone mention that the hyperthreading will not help but if I let
> it there will it be any harm to the system?
> Any comment please.

Sometimes.  Run a test and take a look at your CS (context switch) levels on
VMSTAT.   If they're high, turn HT off.

If it's a dedicated PG system, though, just turn HT off.  We can't use it.

Also, upgrade PostgreSQL to 7.3.8 at least.   7.3.2 is known-buggy.

--
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco

Re: Does "HYPERTHREADING" do any harm if we use with RH9.0

From
Steve Poe
Date:
Josh Berkus wrote:

>Amrit,
>
>
>
>>I use RH 9.0 with postgresql 7.3.2 and 4 Gb ram  [server spec. Dual Xeon
>>3.0] and someone mention that the hyperthreading will not help but if I let
>>it there will it be any harm to the system?
>>Any comment please.
>>
>>
>
>Sometimes.  Run a test and take a look at your CS (context switch) levels on
>VMSTAT.   If they're high, turn HT off.
>
>If it's a dedicated PG system, though, just turn HT off.  We can't use it.
>
>Also, upgrade PostgreSQL to 7.3.8 at least.   7.3.2 is known-buggy.
>
>
>
Sorry for the "dumb" question, but what would be considered high
regarding CS levels?  We just upgraded our server's to dual 2.8Ghz Xeon
CPUs from dual Xeon 1.8Ghz which unfortunately HT built-in.  We also
upgraded our database from version 7.3.4 to 7.4.2

Thanks.

Steve Poe