automatically set processor affinity mask not checked

I take that by default for multi CPU machines, the "Automatically set
processor affinity mask for all processors" is checked in the properties of
the server in SQL 2005
My question is, if its not checked, what does that mean and what are the
pros and cons of it ?Check out sp_configure and the "affinity mask" option. Checking the checkbox means 0 (all processors
can be used). Un.checking this box is setting it to some other bitmask, where you specify which
processors can be used.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi
"Hassan" <hassan@.test.com> wrote in message news:OPwvm$7VIHA.2304@.TK2MSFTNGP06.phx.gbl...
>I take that by default for multi CPU machines, the "Automatically set processor affinity mask for
>all processors" is checked in the properties of the server in SQL 2005
> My question is, if its not checked, what does that mean and what are the pros and cons of it ?
>
>|||So how can I check which processors are being used ?
If I look at the processors, all the processors are checked ?
So in essence, is it the same thing as if this setting was checked ?
"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:A1C1FE69-965D-4A38-B1B8-D61E5CB38CD0@.microsoft.com...
> Check out sp_configure and the "affinity mask" option. Checking the
> checkbox means 0 (all processors can be used). Un.checking this box is
> setting it to some other bitmask, where you specify which processors can
> be used.
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://sqlblog.com/blogs/tibor_karaszi
>
> "Hassan" <hassan@.test.com> wrote in message
> news:OPwvm$7VIHA.2304@.TK2MSFTNGP06.phx.gbl...
>>I take that by default for multi CPU machines, the "Automatically set
>>processor affinity mask for all processors" is checked in the properties
>>of the server in SQL 2005
>> My question is, if its not checked, what does that mean and what are the
>> pros and cons of it ?
>>
>|||> So how can I check which processors are being used ?
Configured to be used, or actually doing some work at a particular point in time? For the later, you
can for instance use Task Manager. For the former, check your sp_configure setting.
> If I look at the processors, all the processors are checked ?
> So in essence, is it the same thing as if this setting was checked ?
There is a slight difference between having all checked and the checkbox not checked (the later is
value 0). SQL Server has as many schedulers as processors. With value 0, a scheduler isn't tied to a
particular processor. With anything but 0, each scheduler is tied to a particular processor. If you
want to dig more into schedulers, threads, workers etc, check out Kalen's Inside SQL Server 2005
book.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi
"Hassan" <hassan@.test.com> wrote in message news:eMOEut8VIHA.5132@.TK2MSFTNGP02.phx.gbl...
> So how can I check which processors are being used ?
> If I look at the processors, all the processors are checked ?
> So in essence, is it the same thing as if this setting was checked ?
> "Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in message
> news:A1C1FE69-965D-4A38-B1B8-D61E5CB38CD0@.microsoft.com...
>> Check out sp_configure and the "affinity mask" option. Checking the checkbox means 0 (all
>> processors can be used). Un.checking this box is setting it to some other bitmask, where you
>> specify which processors can be used.
>> --
>> Tibor Karaszi, SQL Server MVP
>> http://www.karaszi.com/sqlserver/default.asp
>> http://sqlblog.com/blogs/tibor_karaszi
>>
>> "Hassan" <hassan@.test.com> wrote in message news:OPwvm$7VIHA.2304@.TK2MSFTNGP06.phx.gbl...
>>I take that by default for multi CPU machines, the "Automatically set processor affinity mask for
>>all processors" is checked in the properties of the server in SQL 2005
>> My question is, if its not checked, what does that mean and what are the pros and cons of it ?
>>
>>
>sql