ithreads & linux SMP

Discussion in 'Perl Misc' started by none, Feb 18, 2006.

  1. none

    none Guest

    If I use fedora core 2 linux with SMP enabled, perl ithreads, and an
    intel hyper-threaded server with ram in both banks, will a perl program
    that uses ithreads to launch threads launch a thread on each
    "processor"?

    My motherboard used to show 2 cpus with my old linux distro (redhat
    8?), but now it is not showing that with top.

    I am trying to test a threaded application before going out and buying
    a dual core server. I happen to have this hyper threaded machine and am
    testing it out, but have been unable to confirm that the ithreads will
    take advantage of hyper-threading or a dual core cpu.

    Top does not show 2 cpu's, although I am sure the previous install of
    redhat 8 or 9 that I had did reflect that. dmesg reports 2 cpu's.
    Again, this is not a dual core or dual processor machine, it is an
    intel hyper-threaded machine.

    I am hoping that I can buy a dual core machine and use some form of
    perl threads to improve performance of a custom application.

    Linux localhost.localdomain 2.6.11-1.1369_FC4smp #1 SMP Thu Jun 2
    23:08:39 EDT 2005 i686 i686 i386 GNU/Linux

    This is perl, v5.8.6 built for i386-linux-thread-multi

    from dmesg:
    Processor #0 15:2 APIC version 20
    Processor #1 15:2 APIC version 20
    Initializing CPU#0
    Initializing CPU#1
    none, Feb 18, 2006
    #1
    1. Advertising

  2. none

    Guest

    "none" <> wrote:
    > If I use fedora core 2 linux with SMP enabled, perl ithreads, and an
    > intel hyper-threaded server with ram in both banks, will a perl program
    > that uses ithreads to launch threads launch a thread on each
    > "processor"?


    Last time I tested hyperthreading, my conclusion was that yes, it would use
    both "processors", but doing so didn't provide much, if any, advantage
    under my typical workload. (As opposed to real multiple processors or
    dual-core processors, which did provide an advantage--to the extent the job
    was parallelizable, anyway.)


    > My motherboard used to show 2 cpus with my old linux distro (redhat
    > 8?), but now it is not showing that with top.
    >
    > I am trying to test a threaded application before going out and buying
    > a dual core server.


    If you want to know how your application will perform on a dual core
    machine, you need to test it on a dual core machine. Testing it on a
    hyperthreaded machine will be useless or worse.

    > I happen to have this hyper threaded machine and am
    > testing it out, but have been unable to confirm that the ithreads will
    > take advantage of hyper-threading or a dual core cpu.


    That would be like test-driving a Fiat in order to decide if you want
    to buy a Ford. Hey, they both start with F, right?


    Xho

    --
    -------------------- http://NewsReader.Com/ --------------------
    Usenet Newsgroup Service $9.95/Month 30GB
    , Feb 18, 2006
    #2
    1. Advertising

  3. none

    Guest

    By the way (not related to perl), to view the two processors in fedora
    versions of top, hyperthreading or dual-CPU (top won't know the
    difference), hit the 1 (that's "one") key. The screen display will
    toggle CPU usage as a total or for each CPU.
    , Feb 28, 2006
    #3
  4. none

    none Guest

    thankyou for the wonderful insightful advice on how top works and how
    it is useless for me to test on a hyperthreaded machine.

    back to my original question, does perl ithreads use both processors on
    a dual core machine or not?

    keeping in mind that some thread packages do NOT take advanatge of more
    than one processor, does this one do it (ithreads)?
    none, Mar 9, 2006
    #4
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Taewoon Kwon

    Qustion about ithreads join

    Taewoon Kwon, Sep 10, 2004, in forum: Perl
    Replies:
    1
    Views:
    420
    Joe Smith
    Sep 15, 2004
  2. Garry Hodgson
    Replies:
    5
    Views:
    714
  3. David Morel

    Is the ithreads implementation safe?

    David Morel, Sep 13, 2003, in forum: Perl Misc
    Replies:
    0
    Views:
    90
    David Morel
    Sep 13, 2003
  4. Walter Roberson

    Knight's tour in perl ithreads

    Walter Roberson, Feb 2, 2004, in forum: Perl Misc
    Replies:
    0
    Views:
    100
    Walter Roberson
    Feb 2, 2004
  5. Walter Roberson

    ithreads at runtime?

    Walter Roberson, Feb 3, 2004, in forum: Perl Misc
    Replies:
    3
    Views:
    87
    Walter Roberson
    Feb 4, 2004
Loading...

Share This Page