Dedicating a processor

By kenterm ยท 9 replies
Dec 3, 2007
  1. If you have a multi-processor CPU, WinXp Pro allows you to dedicate any percentage of any processor to a "Process" as listed in Task Manager by right clicking on the process name and clicking Set Affinity.

    I would like to dedicate to a disk partition instead. I have heard that IBM servers have this capability. Does Xp? I have been unable to find an answer or method. Thanks for any guidance.

    See profile for configuration.
  2. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    Uhm.. What?! You want to dedicate a disk partition to a process? What for? Just set up the program that all its files are on that other partition? Or you want to swap on a specific partition?
  3. kenterm

    kenterm TS Rookie Topic Starter

    Thanks for the reply.

    Currently I keep "Windows & Data Files" in partition #1. "Application Program Files" are kept in partition #2.

    Partition #1 is assigned Processor Core 0 by default.

    Processor "intensive" programs contained on partition #2 are assigned Processor Core 1. This is done by starting the desired program and then going to in Task Manager and assigning Process Core 1 to the "Process" associated
    with that program.

    This significantly increases the program speed and is an excellent way to utilize the second core. I think this is because windows does not need to use the two cores at the same time and therefore wastes the second one.

    However, this must be done for every program on partition #2 if I want to optimize each program. There are many and this is a pain. It would be much easier if I could dedicate Processor Core 1 to the whole Applications Program partition [#2] and be done with it.

    I just can't find out if dedicating a processor to a partition is only available on IBM servers or whether it is available in WinXp.

    Here is the IBM article I am referencing.
  4. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,742   +421

    I believe you are incorrect there. XP utilizes both cores for Windows just fine. You can notice this by opening up task manager and looking at the processor usage graphs. If one was being wasted, it would show 0% all the time, but this does not happen. Certain programs don't utilize both cores, but others do. Forcing them to run on only one core doesn't make any sense, so I think your logic behind wanting to do what you are trying to describe is faulty.
  5. kenterm

    kenterm TS Rookie Topic Starter

    Yes But

    You are correct that Windows uses both processors and I have looked at the graphs you mention. All Processes by default are set up to use both cores. I just disable core 0 on my processor intensive programs - all the others stay with both. But something must be working because the response times of the core 1 only programs is really noticable. Big time. Any guesses why?

    You make a good point about not all programs can use multi-processors. Is there a way to know which ones do?

    Thanks again.
  6. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    So actually you want certain programs to always have their CPU affinity set.

    Do use the forums search feature next time:

    As for the "really noticeable" performance increase.. Are you sure it is because of the CPU affinity and not the process priority setting?

    You can get some performance boost from fixing a thread to a CPU, but I don't think that can be categorised as "really noticeable".

    And as SNGX said, Windows tries to balance processes between CPUs so that they are all equally used. This dynamic scheduling occurs in real time and in most cases is better than anything you can do manually. You should set the CPU affinity only when you are running one or two single-threaded really CPU-intensive applications.
  7. kenterm

    kenterm TS Rookie Topic Starter

    Thanks to both Nodsu & SNGX for their input.

    I had not changed the process priority setting so I can't really explain the increase in performance but since it does exist I will leave the two processor intensive programs set up the way they are using Core 1 and I will not fool around with any others and let Windows do its thing as you suggest. One of my questions is still unanswered.

    Is there any way I can determine if a program will use more than one processor? I thought that would be controlled by the OS but I think you impllied it was application program driven. Can I determine this?

    Thanks for all of the useful info.

    Regards - Ken Terminini
  8. jobeard

    jobeard TS Ambassador Posts: 11,166   +986

    multicore processors are just another name for SMP: Symmetric Multi Processing.

    Tuning an SMP system is a full time career in it self; even the big boys have problems 'getting it right'.
    There's a lot of background information that needs to be acquired to understand
    the work loads and which processes *might* benefit from isolation from which other(s).

    The best choice on SMP (ie multicore) PCs is to leave everything alone and let
    the OS do its thing -- after all, most PCs are desktop systems and there are
    no long running processes anyway.

    On Win/NT with IIS installed, a multicore system will automatically place IIS on
    one core and the TCP Kernel thread on another. (this is very old news :) )
  9. kenterm

    kenterm TS Rookie Topic Starter


    OK - 3 heavies telling me to keep my hands off trying to tune a dual core system is enough! Everything has been set back to default settings. This is a business system and I need stability. I came in here for answers and got them. I am taking the advice. Thanks to all!
  10. bushwhacker

    bushwhacker TechSpot Chancellor Posts: 783

    Then you need to speak to one of IT people for more information.
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