hyper threading: enabled

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Wednesday, March 7, 2012

Hyperthreading

Hi,
I have a 4 processor server with hyperthreading enabled. The
processors show up in SQL as Processors 0-7. My question is, which numbers
are physical processors and which numbers are the virtual/hyperthreaded
processors? The reason I want to know is that I want to take away 1 physical
and 1 virtual processor from the processors that SQL is allowed to use.
Thanks,
ScottThe firmware/hardware manufacturers are recommended by Intel to make it like following:
Phy0 = Log0
Phy1 = Log1
Phy2 = Log2
Phy3 = Log3
Phy0 = Log4
Phy1 = Log5
Phy2 = Log6
Phy3 = Log7
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
Blog: http://solidqualitylearning.com/blogs/tibor/
"Scott" <Scott@.discussions.microsoft.com> wrote in message
news:9095D9D1-FE9A-4536-8BA7-96FF93634660@.microsoft.com...
> Hi,
> I have a 4 processor server with hyperthreading enabled. The
> processors show up in SQL as Processors 0-7. My question is, which numbers
> are physical processors and which numbers are the virtual/hyperthreaded
> processors? The reason I want to know is that I want to take away 1 physical
> and 1 virtual processor from the processors that SQL is allowed to use.
> Thanks,
> Scott|||"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:eE9lDgcmFHA.3544@.TK2MSFTNGP15.phx.gbl...
> The firmware/hardware manufacturers are recommended by Intel to make it
> like following:
> Phy0 = Log0
> Phy1 = Log1
> Phy2 = Log2
> Phy3 = Log3
> Phy0 = Log4
> Phy1 = Log5
> Phy2 = Log6
> Phy3 = Log7
>
So if I am reading this correctly, if I wanted to remove the 4th processor
(both physical and hyperthreaded), I would remove the Log3 and Log7...
Rick Sawtell|||So, 0-3 are physical processors and 4-7 are virtual/hyperthreaded?
"Tibor Karaszi" wrote:
> The firmware/hardware manufacturers are recommended by Intel to make it like following:
> Phy0 = Log0
> Phy1 = Log1
> Phy2 = Log2
> Phy3 = Log3
> Phy0 = Log4
> Phy1 = Log5
> Phy2 = Log6
> Phy3 = Log7
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
> Blog: http://solidqualitylearning.com/blogs/tibor/
>
> "Scott" <Scott@.discussions.microsoft.com> wrote in message
> news:9095D9D1-FE9A-4536-8BA7-96FF93634660@.microsoft.com...
> > Hi,
> > I have a 4 processor server with hyperthreading enabled. The
> > processors show up in SQL as Processors 0-7. My question is, which numbers
> > are physical processors and which numbers are the virtual/hyperthreaded
> > processors? The reason I want to know is that I want to take away 1 physical
> > and 1 virtual processor from the processors that SQL is allowed to use.
> >
> > Thanks,
> > Scott
>|||> So if I am reading this correctly, if I wanted to remove the 4th processor (both physical and
> hyperthreaded), I would remove the Log3 and Log7...
Yep.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
Blog: http://solidqualitylearning.com/blogs/tibor/
"Rick Sawtell" <r_sawtell@.hotmail.com> wrote in message
news:ejUJKjcmFHA.3336@.tk2msftngp13.phx.gbl...
> "Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in message
> news:eE9lDgcmFHA.3544@.TK2MSFTNGP15.phx.gbl...
>> The firmware/hardware manufacturers are recommended by Intel to make it like following:
>> Phy0 = Log0
>> Phy1 = Log1
>> Phy2 = Log2
>> Phy3 = Log3
>> Phy0 = Log4
>> Phy1 = Log5
>> Phy2 = Log6
>> Phy3 = Log7
>>
> So if I am reading this correctly, if I wanted to remove the 4th processor (both physical and
> hyperthreaded), I would remove the Log3 and Log7...
>
> Rick Sawtell
>|||I'm not sure that you refer to the two logical processors on one physical processor as
"virtual/hyperthreader" vs "physical". But, yes, you get the idea.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
Blog: http://solidqualitylearning.com/blogs/tibor/
"Scott" <Scott@.discussions.microsoft.com> wrote in message
news:0B568019-6053-43F8-8B35-D79FBEF32C9D@.microsoft.com...
> So, 0-3 are physical processors and 4-7 are virtual/hyperthreaded?
>
> "Tibor Karaszi" wrote:
>> The firmware/hardware manufacturers are recommended by Intel to make it like following:
>> Phy0 = Log0
>> Phy1 = Log1
>> Phy2 = Log2
>> Phy3 = Log3
>> Phy0 = Log4
>> Phy1 = Log5
>> Phy2 = Log6
>> Phy3 = Log7
>> --
>> Tibor Karaszi, SQL Server MVP
>> http://www.karaszi.com/sqlserver/default.asp
>> http://www.solidqualitylearning.com/
>> Blog: http://solidqualitylearning.com/blogs/tibor/
>>
>> "Scott" <Scott@.discussions.microsoft.com> wrote in message
>> news:9095D9D1-FE9A-4536-8BA7-96FF93634660@.microsoft.com...
>> > Hi,
>> > I have a 4 processor server with hyperthreading enabled. The
>> > processors show up in SQL as Processors 0-7. My question is, which numbers
>> > are physical processors and which numbers are the virtual/hyperthreaded
>> > processors? The reason I want to know is that I want to take away 1 physical
>> > and 1 virtual processor from the processors that SQL is allowed to use.
>> >
>> > Thanks,
>> > Scott
>>|||Actually even though they suggest that there are several variations. There
is a utility on Intel's web site (somewhere<g>) that will supposedly show
you the layout for that particular configuration.
--
Andrew J. Kelly SQL MVP
"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:eE9lDgcmFHA.3544@.TK2MSFTNGP15.phx.gbl...
> The firmware/hardware manufacturers are recommended by Intel to make it
> like following:
> Phy0 = Log0
> Phy1 = Log1
> Phy2 = Log2
> Phy3 = Log3
> Phy0 = Log4
> Phy1 = Log5
> Phy2 = Log6
> Phy3 = Log7
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
> Blog: http://solidqualitylearning.com/blogs/tibor/
>
> "Scott" <Scott@.discussions.microsoft.com> wrote in message
> news:9095D9D1-FE9A-4536-8BA7-96FF93634660@.microsoft.com...
>> Hi,
>> I have a 4 processor server with hyperthreading enabled. The
>> processors show up in SQL as Processors 0-7. My question is, which
>> numbers
>> are physical processors and which numbers are the virtual/hyperthreaded
>> processors? The reason I want to know is that I want to take away 1
>> physical
>> and 1 virtual processor from the processors that SQL is allowed to use.
>> Thanks,
>> Scott
>

Sunday, February 19, 2012

Hyper Threading SQL 2000 Ent, Windows 2003 4GB RAM -> "Yes" or "No

Hi
What would be the best practice on subject? Are there any resources I should
read?
Our server have 2xXEON CPU's and 4 with HT (All are enabled on our SQL
2000), but we have some performance issue.
Thanks
Have a look here:
http://blogs.msdn.com/slavao/archive...12/492119.aspx
Bottom line is that you don't know for sure until you test it both ways
under the exact conditions you will run with. Sometimes it helps sometimes
it hurts.
Andrew J. Kelly SQL MVP
"Core" <Core@.discussions.microsoft.com> wrote in message
news:3E7FB0BD-07D0-426D-94D3-4BE515D0FE7A@.microsoft.com...
> Hi
> What would be the best practice on subject? Are there any resources I
> should
> read?
> Our server have 2xXEON CPU's and 4 with HT (All are enabled on our SQL
> 2000), but we have some performance issue.
> Thanks

Hyper Threading SQL 2000 Ent, Windows 2003 4GB RAM -> "Yes" or "No

Hi
What would be the best practice on subject? Are there any resources I should
read?
Our server have 2xXEON CPU's and 4 with HT (All are enabled on our SQL
2000), but we have some performance issue.
ThanksHave a look here:
http://blogs.msdn.com/slavao/archiv.../12/492119.aspx
Bottom line is that you don't know for sure until you test it both ways
under the exact conditions you will run with. Sometimes it helps sometimes
it hurts.
Andrew J. Kelly SQL MVP
"Core" <Core@.discussions.microsoft.com> wrote in message
news:3E7FB0BD-07D0-426D-94D3-4BE515D0FE7A@.microsoft.com...
> Hi
> What would be the best practice on subject? Are there any resources I
> should
> read?
> Our server have 2xXEON CPU's and 4 with HT (All are enabled on our SQL
> 2000), but we have some performance issue.
> Thanks

Hyper Threading - Good or Bad?

Ello,

We have quite a few SQL Servers running on servers with hyper threaded enabled processors. We have always left hyper threading on, even on our very busy servers but i've recently begun to question this due to comments i have received.

All our servers run SQL 2000 SP3a as "support" for hyper threading was added in SP3a

So... What do you think of Hyper Threading any why?Never had the need...I'll have to read up on this....|||OK, I'll go with gimicky

www.microsoft.com/sql/howtobuy/SQLonHTT.doc

Just scale the box|||Thanks Brett.

It will be good to compare notes, my hunt for information has not found much for or against yet although when trouble shooting we are now always advised to turn it off...

This link to a newgroup article raised my eyebrow
News Group (http://groups.google.co.uk/group/microsoft.public.sqlserver.server/browse_frm/thread/99860c74db9d183/af9e69650569f1db?lnk=st&q=hyper+threading+%2B+SQL+performance&rnum=2&hl=en#af9e69650569f1db)

Quoting a MVP from the link he says

The problem with a HT CPU that the 2 simultaneous threads running on the CPU both contend for the *same* L1, L2 and L3 processor cache. During heavy processing, you may actually have the 2 clearing each other's cache. This results in each having to go to main system RAM to work.

But read the whole thing for context as he also talks about parallelism|||Yes i read that but the other post has spurred me on to get the internet shovel out and keep hunting for more information and post for peoples experiences.

:D|||I have been told that Windows Server 2003 has better support for Hyperthreading. If you can, get your SQL Servers running on 2003, and all should be well. We have had no problems on 2003, or 2000, though.

Wednesday, March 7, 2012

Hyperthreading

Hyperthreading

Hyperthreading

Sunday, February 19, 2012

Hyper Threading SQL 2000 Ent, Windows 2003 4GB RAM -> "Yes" or "No

Hyper Threading SQL 2000 Ent, Windows 2003 4GB RAM -> "Yes" or "No

Hyper Threading - Good or Bad?

hyper threading

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