topic Re: How many threads per core are supported for intel Xeon proc in Intel® Moderncode for Parallel Architectures

How many threads per core are supported for intel Xeon processor

bharatipingale — Wed, 10 Sep 2008 07:45:20 GMT

Hi all,

For Intel Xeon processor, How many threads per core supported?

We can have example of Ultrasparc T1 processor which supports 4-8 cores per chip and 4 SMt threads per core. So which inreases its processing power.

Please share your views.

Thanks in advance,
Bharati

Re: How many threads per core are supported for intel Xeon proc

Huseyin_A_Intel1 — Tue, 30 Sep 2008 11:54:15 GMT

Hi,

We have SMT support in our next generation Intel microarchitecture. There will be 2 threads per core and you can find more information aboutit here: http://www.intel.com/technology/architecture-silicon/next-gen/?iid=SEARCH

We don't have SMT support in current Core 2 generation microarchitecture. However, we had SMT support (Hyper Threading - again 2 threads per core) insome of the Xeon and Pentium family processors. You can find out more about which products support it here: http://compare.intel.com/PCC/intro.aspx?iid=processors_body+resources_pcc

I hope this helps to answer your question.

Thanks

Levent

Re: How many threads per core are supported for intel Xeon proc

TimP — Tue, 30 Sep 2008 12:32:11 GMT

Intel HyperThreading doesn't fully meet the description of SMT as presented here http://en.wikipedia.org/wiki/Simultaneous_multithreading even though P4 is cited as an example. Neither Intel nor Sun "SMT" support issue of instructions from more than one thread per cycle, as multiple cores do. HT processors duplicate some of the resources (e.g. registers directly accessible by program) and share others, including instruction issue and arithmetic units. HT on Nehalem provides more flexible sharing of certain resources than did HT on P4.

As the cited article states, a primary motivation is "hiding memory latency" by allowing a rapid switch to another thread when a thread is stalled by cache misses. As the Intel CPUs which have implemented HT have a relatively slow sqrt instruction, those few applications which spend about half their time executing sqrt also are good HT candidates. These are examples of application and CPU dependent issues where SMT may contribute significantly to performance.

Re: How many threads per core are supported for intel Xeon proc

Tan-Killer — Sat, 07 Feb 2009 02:53:49 GMT

Quoting - bharatipingale

I use Xeon X3220 for Web Server

now i'm need to know about multi-thread on Apache2 web server

someone can help me?

Re: How many threads per core are supported for intel Xeon proc

robert-reed — Sat, 07 Feb 2009 21:30:21 GMT

Quoting - Tan-Killer

I use Xeon X3220 for Web Server

now i'm need to know about multi-thread on Apache2 web server

someone can help me?

You want to multi-thread Apache2? Apache is already threaded. You might have more succes at the Apache web site, where you can pick up such tidbits as the one I acquired just now:

StartThreads Directive
Description: Number of threads created on startup
Syntax: StartThreads number
Default: See usage for details
Context: server config
Status: MPM
Module: beos, mpm_netware

Number of threads created on startup. As the number of threads is dynamically controlled depending on the load, there is usually little reason to adjust this parameter.

For mpm_netware the default is StartThreads 50 and, since there is only a single process, this is the total number of threads created at startup to serve requests.

For beos the default is StartThreads 10. It also reflects the total number of threads created at startup to serve requests.

If you could be more specific about your question, we might be able to provide you a better answer.

Re: How many threads per core are supported for intel Xeon proc

Tan-Killer — Sun, 08 Feb 2009 04:55:08 GMT

Quoting - Robert Reed (Intel)

You want to multi-thread Apache2? Apache is already threaded. You might have more succes at the Apache web site, where you can pick up such tidbits as the one I acquired just now:

StartThreads Directive
Description: Number of threads created on startup
Syntax: StartThreads number
Default: See usage for details
Context: server config
Status: MPM
Module: beos, mpm_netware

Number of threads created on startup. As the number of threads is dynamically controlled depending on the load, there is usually little reason to adjust this parameter.

For mpm_netware the default is StartThreads 50 and, since there is only a single process, this is the total number of threads created at startup to serve requests.

For beos the default is StartThreads 10. It also reflects the total number of threads created at startup to serve requests.

If you could be more specific about your question, we might be able to provide you a better answer.

Thank you for your answer

i have question with multi-thread

Is MySQL servercan do?

Re: How many threads per core are supported for intel Xeon proc

gaston-hillar — Thu, 12 Mar 2009 02:03:13 GMT

Quoting - Tan-Killer

Thank you for your answer

i have question with multi-thread

Is MySQL servercan do?

Yes, MySQL is also capable of taking advantage of multiple processors or multiple cores.
Take into account that you can configure that in MySQL, you can limit the number of cores that the database engine can use.

Cheers,

Gastn

Re: How many threads per core are supported for intel Xeon proc

gaston-hillar — Mon, 16 Mar 2009 19:48:49 GMT

Quoting - Levent (Intel)

Hi,

We have SMT support in our next generation Intel microarchitecture. There will be 2 threads per core and you can find more information aboutit here: http://www.intel.com/technology/architecture-silicon/next-gen/?iid=SEARCH

We don't have SMT support in current Core 2 generation microarchitecture. However, we had SMT support (Hyper Threading - again 2 threads per core) insome of the Xeon and Pentium family processors. You can find out more about which products support it here: http://compare.intel.com/PCC/intro.aspx?iid=processors_body+resources_pcc

I hope this helps to answer your question.

Thanks

Levent

Hi,

This post in this community can help: http://software.intel.com/en-us/articles/hyper-threading-technology-multi-core-and-mobile-intel-pentium-processor-m-toolbox/
It includes a library and C++ code to detect multiple physical and logical cores. Cool.