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proformance boost, maybe?

Discussion in 'Team OcUK Distributed Computing Projects' started by shadowscotland, 10 Jul 2006.

  1. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    Question to the more technically minged out their.

    I've got Fah set up as a service on all the workstation here and as such it starts with out the need to log on.

    Theirfore will the machine fold quicker if left at log in prompt? Due to windows not using up resources.

    Running XP pro

    Usually not an issue as user will be using each an ever PC but this week we've got a few empty seats. Just thought I'd ask
     
  2. PhilthyPhil

    Mobster

    Joined: 19 Oct 2002

    Posts: 2,696

    Location: UK

    You should see a bit of a boost... how much depends on how heavily the machines are used when users are logged on though I guess, if they are just used for surfing or whatever there probably won't be a huge difference.
     
  3. oceaness

    Wise Guy

    Joined: 7 Dec 2005

    Posts: 1,667

    Location: Hartley

    There will be a slight performance increase due to the fact that windows wont start many of it's processes.

    For example I currently have 49 running processes, when I log off alot of those stop. Obviously there wont be a lot of difference if the machines are not heavily used when they are logged on as most of the services use very little CPU anyway.
     
  4. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    Thanks guys

    That's what I thought. I'll benchmark some times and report back any surprises.
     
  5. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    Ok done the tests and

    1) non-loged in pc - steps average 12mins 40
    (max 12:58, Min 12:31)

    2) Loged on PC (no users) steps average 12:27
    (max 13:02, Min 12:13)

    3) Loged on PC (with user - word/excel ) steps average 13:20
    (max 13:55, Min 12:23)

    SSE boost active in all three cases

    Observations
    Max maximum fold time with user actively working (no prizes their)
    Simular Maximum fold times with out user, with and without login (not quite expected)
    But lower average times when loged in!
    (with exception of 13:02 all other results below 12:30 aka Minimum time with 1)

    So it look like windows fully running (no screen saver) will process this particular single WU faster than windows at login screen.
    Ok it's only 2% quicker but still.



    I'll do tests on multi thread tomorrow and report back
     
    Last edited: 10 Jul 2006
  6. BillytheImpaler

    Man of Honour

    Joined: 2 Aug 2005

    Posts: 8,741

    Location: Cleveland, Ohio, USA

    Wow, SS, that is interesting. Does anybody have any theories as to why that might be?
     
  7. joeyjojo

    Soldato

    Joined: 2 Dec 2005

    Posts: 5,519

    Location: Herts

    Anomalous results due to flaws in the method tbh :p

    If not then I have no idea why that would be. Does windows behave differently with cpu/memory allocation at the login screen?
     
  8. Joe42

    Mobster

    Joined: 18 Jan 2005

    Posts: 4,172

    Location: Northants

    I wonder if there are any optimisations that start running when its logged on.

    I'm thinking maybe it does more paging and such and frees up more memory when its logged on for folding to use. Perhaps there is a process that optimises memory or does paging or something that only starts when its logged on.
     
  9. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    Pc just started crunching a new 56 pointer (1700) previous was 1702

    Still doing sub 12:20 steps so it's not single WU specific (possable core specific?)
     
  10. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    20 plus folds used to calculate each average (mean)
    The Mean calc'ed with out highest and lowest give result within 3 sec's but infavour of findings :p
    Aka 1) 12:42 and 2) 12:24

    Edit: 512MB Ram not ever half used with a 1700
     
    Last edited: 10 Jul 2006
  11. shadowscotland

    Sgarrista

    Joined: 31 May 2006

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    Location: West London

    found this on http://www.gromacs.org/external/search.html

    Is there any way I can make GROMACS run faster?

    That depends on your setup. If you are using x86 processors you should definitely make sure that you compile GROMACS with assemblt loops, and that your OS supports SSE instructions if you are using Pentium III/IV processors. If you compiled GROMACS with assembly loops there will be a line in the logfile telling you which loops we are using.
    On alpha hardware you might want to play around with enabling/disabling the software invsqrt, and the inner loop vectorization. Modern alpha chips have a fairly fast hardware sqrt, but they also seem to benefit even more from vectorizing the innerloops and using the vectorized invsqrt provided in GROMACS.
    If you are using IBM hardware you should locate or download the MASS libraries (mathematical accelerated subsystem). If you provide the location of this library in the LDFLAGS environment variable GROMACS will automatically use fast vectorized inner loops on IBM. (are these subsystem only active post login? just a thought)
    On any system apart from Linux/x86 (where we use assembly innerloops) you should also try to use a fortran compiler for better performance, and if you run Linux/alpha you should use the Compaq compilers instead of gcc.

    Edit: intresting reading but a bit over my head :o
     
    Last edited: 10 Jul 2006
  12. Mattus

    Capodecina

    Joined: 30 Sep 2003

    Posts: 10,916

    Location: London

    I think all that relates to the GROMACS code before it's compiled and packaged, as opposed to on our machines.

    It's interesting. I can't think of why it would be faster logged on than logged off. Seems a little strange unless there is some kind of hardware-specific driver which is only enabled when the user's logged on.
     
  13. joeyjojo

    Soldato

    Joined: 2 Dec 2005

    Posts: 5,519

    Location: Herts

    Can't find anything on this. No ideas

    shadowscotland - was joking hence the :p , good work, but you've got us all stumped :mad: :)
     
  14. RobOC

    Hitman

    Joined: 11 Nov 2004

    Posts: 522

    I'd say the two results are similar enough to discount them as equal, and that there isn't enough in it to worry about. The only benefit I can see crunching at the login screen might give is extra memory on PCs that don't have much as things like explorer aren't running yet, but in 99% of cases I'd say it makes no odds.
     
  15. shadowscotland

    Sgarrista

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    Location: West London

    I hear what your all saying - and I agree, just thought I'd post my results as they were the opposite of what I expected.

    We had a power cut this morning so twin thread results will be posted at lunchtime now. (see new thread for this morning folding problems :( )
     
  16. RobOC

    Hitman

    Joined: 11 Nov 2004

    Posts: 522

    Definitely, it is always interesting to see the results of these sorts of tests.
     
  17. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    duel threads

    Ok duel thread results

    1) non-loged in pc
    Thread 1 - steps average 9mins 52 (max 10:00, Min 9:50)
    Thread 2 - steps average 21mins 46 (max 21:56, Min 21:41)

    2) loged in pc
    Thread 1 - steps average 9mins 53 (max 9:54, Min 9:52)
    Thread 2 - steps average 21mins 47 (max 21:50, Min 21:45)

    no real differances except range of results more varied in non-loged period.

    Different machine to single thread results.
     
  18. rich99million

    Sgarrista

    Joined: 26 Dec 2002

    Posts: 9,348

    Location: Derbyshire

    I won't be leaving my machine logged in at home whatever results you find - teenage boy syndrome sufferer here :p

    though when I came home today to find my monitor switched on and the WinXP login screensaver that did make me wonder if that would make much difference, it's only a WinXP logo which appears at random positions on the screen so can't be as bad as a fully animated one - anyone know if you can disable it though? :confused:
     
  19. shadowscotland

    Sgarrista

    Joined: 31 May 2006

    Posts: 7,560

    Location: West London

    Right click desktop.
    Properties.
    screen saver tab
    screen saver drop down menu (blue downwards arrow ;) )
    select "(none)"
     
  20. RobOC

    Hitman

    Joined: 11 Nov 2004

    Posts: 522