From chemistry-request&$at$&ccl.net Tue Feb 8 15:30:52 2005 Received: from relay-1.mail.nethere.net (relay-1.mail.nethere.net [66.63.128.161]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id j18KUni8020496 for ; Tue, 8 Feb 2005 15:30:49 -0500 Received: from scan-1.mail.nethere.net (scan-1.mail [66.63.128.132]) by relay-1.mail.nethere.net (Postfix) with ESMTP id 73AC412BE90; Tue, 8 Feb 2005 10:53:02 -0800 (PST) Received: from mta-2.mail.nethere.net by scan-1.mail.nethere.net with LMTP id 63405-68; Tue, 8 Feb 2005 10:53:02 -0800 (PST) Received: from coffee (unknown [207.167.99.153]) by mta-2.mail.nethere.net (Postfix) with ESMTP id D5D9C87F42; Tue, 8 Feb 2005 10:53:01 -0800 (PST) From: "Ross Walker" To: "'Steve Bowlus'" , "'Rodrigo Pontes'" , Subject: RE: CPU usage Date: Tue, 8 Feb 2005 10:53:01 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_03AC_01C50DCC.5C102AA0" X-Mailer: Microsoft Office Outlook, Build 11.0.6353 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Thread-Index: AcUNqaBNxxE2j+TsTkCumfPPbOcZqQAZIy4w In-Reply-To: Message-Id: <20050208185301.D5D9C87F42(at)mta-2.mail.nethere.net> X-Spam-Status: No, hits=4.6 required=7.5 tests=HTML_30_40,HTML_FONTCOLOR_BLUE, HTML_MESSAGE,MK_YAHOO_REDIR_01,MY_HTML_OBFU,NO_RDNS,WLS_URI_OPT_150 autolearn=no version=2.61 X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net This is a multi-part message in MIME format. ------=_NextPart_000_03AC_01C50DCC.5C102AA0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit You can lock the processor affinity of a process under windows by running task manager and right clicking on the process and selecting set affinity. You will need to do this with Gaussian's master thread so that all sub threads inherit this affinity. Also, you should double check what you mean by 60% usage. Do you mean 60% of one cpu or 60% of the total? The bar on the left in task manager is the total cpu usage, while the graphs are individual cpu usage. So on a REAL dual cpu machine running one process this bar would show 50% usage. My understanding is that Gaussian under windows is single cpu so this is the best you can hope for. In hyper threaded environments things are a lot more complicated since you don't actually have two cpus, just two pipelines. Hence the total cpu usage gauge can be deceptive... Note, if you manually switch hyper threading off in the bios and still see only 60% cpu utilisation then chances are the process is spending most of its time waiting for memory or swap rather than doing computation. In this case there is not much you can do as you are limited by the machine architecture. So, short answer. "On a hyper threaded machine don't worry about the cpu usage bar it is deceptive.". Only on a real dual cpu machine or single cpu machine is it accurate. All the best Ross /\ \/ |\oss Walker | Department of Molecular Biology TPC15 | | The Scripps Research Institute | | Tel:- +1 858 784 8889 | EMail:- ross(at)rosswalker.co.uk | | http://www.rosswalker.co.uk/ | PGP Key available on request | Note: Electronic Mail is not secure, has no guarantee of delivery, may not be read every day, and should not be used for urgent or sensitive issues. _____ From: Computational Chemistry List [mailto:chemistry-request(at)ccl.net] On Behalf Of Steve Bowlus Sent: 07 February 2005 19:09 To: Rodrigo Pontes; chemistry(at)ccl.net Subject: CCL:CPU usage I have observed the same behavior with another quantum code on a machine with the same CPU/OS combination. There was an earlier post to this list asking about what seemed to be a similar problem with the Xeon HT. I tentatively interpret the behavior that the job is given 100% of one of the HT execution streams, while the other stream is largely kept idle. I have not found a way to tune this behavior. If you look at ControlPanels >AdministrativeTools >ComputerManagement >Processors, you will see there are two CPUs shown. These can be uninstalled, but I haven't tried uninstalling one. Presumably, all CPU resources would be concentrated in a single execution stream, but I haven't found any documentation on this point. I also haven't found anything to suggest the second "CPU" can be _re_installed. I haven't talked to Intel or HP (who built my machine), either of whom could shed light on all these issues. Seems a pity that information on such a feature (or limitation) of HT technology would not be made readily available. sb -----Original Message----- From: Computational Chemistry List [mailto:chemistry-request(at)ccl.net]On Behalf Of Rodrigo Pontes Sent: Monday, February 07, 2005 9:29 AM To: chemistry(at)ccl.net Subject: CCL:CPU usage Dear Colleagues, We are running Gaussian on a Windows XP/Pentiun-IV HT 3.2GHz machine. We observed (in the Task manager / performance) that the CPU usage is only around 60%. Have someone noticed the same problem? How could us set the configuration to a 100% CPU usage? Thanks in advance, Rodrigo M. Pontes Departemanto de Quimica Universidade Estadual de Maringa Brazil _____ Yahoo! Acesso Gratis - Internet rapida e gratis. Instale o discador do Yahoo! agora. ------=_NextPart_000_03AC_01C50DCC.5C102AA0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
You can lock the processor affinity of a = process under=20 windows by running task manager and right clicking on the process and = selecting=20 set affinity. You will need to do this with Gaussian's master thread so = that all=20 sub threads inherit this affinity.
 
Also, you should double check what you mean by = 60% usage.=20 Do you mean 60% of one cpu or 60% of the total? The bar on the left in = task=20 manager is the total cpu usage, while the graphs are individual cpu = usage. So on=20 a REAL dual cpu machine running one process this bar would show 50% = usage. My=20 understanding is that Gaussian under windows is single cpu so this is = the best=20 you can hope for. In hyper threaded environments things are a lot = more=20 complicated since you don't actually have two cpus, just two pipelines. = Hence=20 the total cpu usage gauge can be deceptive...
 
Note, if you manually switch hyper threading = off in the=20 bios and still see only 60% cpu utilisation then chances are the process = is=20 spending most of its time waiting for memory or swap rather than doing=20 computation. In this case there is not much you can do as you are = limited by the=20 machine architecture.
 
So, short answer. "On a hyper threaded machine = don't worry=20 about the cpu usage bar it is deceptive.". Only on a real dual cpu = machine=20 or single cpu machine is it accurate.
 
All the best
Ross
 

/\
\/
|\oss Walker

| Department of = Molecular=20 Biology TPC15 |
| The Scripps Research Institute |
| Tel:- +1 858 = 784 8889=20 | EMail:- ross(at)rosswalker.co.uk |
| http://www.rosswalker.co.uk/ | = PGP Key=20 available on request |

Note: Electronic Mail is not secure, has = no=20 guarantee of delivery, may not be read every day, and should not be used = for=20 urgent or sensitive issues.

 

From: Computational Chemistry List = [mailto:chemistry-request(at)ccl.net] On Behalf Of Steve=20 Bowlus
Sent: 07 February 2005 19:09
To: Rodrigo = Pontes;=20 chemistry(at)ccl.net
Subject: CCL:CPU = usage

I=20 have observed the same behavior with another quantum code on a machine = with=20 the same CPU/OS combination.  There was an earlier post to this = list=20 asking about what seemed to be a similar problem with the Xeon HT.=20
 
I=20 tentatively interpret the behavior that the job is given 100% of one = of the HT=20 execution streams, while the other stream is largely kept idle.  = I have=20 not found a way to tune this behavior. If you look at ControlPanels=20 >AdministrativeTools >ComputerManagement >Processors, = you will=20 see there are two CPUs shown.  These can be uninstalled, but I = haven't=20 tried uninstalling one.  Presumably, all CPU resources would be=20 concentrated in a single execution stream, but I haven't found any=20 documentation on this point.  I also haven't found anything to = suggest=20 the second "CPU" can be _re_installed. 
 
I=20 haven't talked to Intel or HP (who built my machine), either of whom = could=20 shed light on all these issues.  Seems a pity that information on = such a=20 feature (or limitation) of HT technology would not be made readily=20 available.
 
sb
 
 

 -----Original = Message-----
From:=20 Computational Chemistry List [mailto:chemistry-request(at)ccl.net]On = Behalf Of=20 Rodrigo Pontes
Sent: Monday, February 07, 2005 9:29=20 AM
To: chemistry(at)ccl.net
Subject: CCL:CPU=20 usage

Dear Colleagues,
 
We are running Gaussian on a Windows XP/Pentiun-IV HT=20 3.2GHz machine. We observed (in the Task manager / performance) = that=20 the CPU usage is only around 60%. Have someone noticed the = same=20 problem? How could us set the configuration to a 100% CPU = usage?
 
Thanks in advance,
 
Rodrigo M. Pontes
Departemanto de Quimica
Universidade Estadual de Maringa
Brazil

Yahoo!=20 Acesso Gratis - Internet rapida e gratis. Instale o discador do = Yahoo!=20 agora.
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