different CPU load in idling (W2k << Linux2.6 <W98)

Discussion in 'Parallels Desktop for Mac' started by mimi, May 9, 2006.

  1. mimi

    mimi Member

    Messages:
    24
    I noticed that there are quite large differences in the host CPU's load for different guest OSs when they are in idle state. The values monitored by top command were something like:
    Windows2000 3~5 %,
    Linux2.6 ~25% (Scientific linux4.2, a free version of RH Enterprise),
    Windows98se ~30%.

    I don't care for Win98, however, such a large load for linux disappointed me.:confused:
    I remember that a typical load for Win2K was also about 30% in earlier betas. So can I expect lower CPU load for linux in later betas:) ?

    MBP 2G, 2Gmem, PW2.1 beta6.
     
  2. drtimhill

    drtimhill Member

    Messages:
    85
    Did you select the correct OS in the PW Edit dialog? This can make a difference.

    However, to an extent this is to be expected: an "idle" operating system is still doing _something_, and how each OS handles idle varies. Most VM systems (I assume, including PW) try to detect these idle states and switch away from the OS when this occurs. For example, deep in the bowels of WinXP is (in effect) a system idle thread that just executes a HLT instruction to stop the CPU when nothing else is happening. PW can detect this (in fact, OS X can also) and switch away from the thread. However, some system such as earlier Windows systems don't do this can can always appear "busy". This is why you see such different % times during so-called "idle".

    --Tim
     
  3. mimi

    mimi Member

    Messages:
    24
    Errata: CPU usage in idle state (W2K << Linux <<< W98 )

    Tim,
    thank you for your reply and I am sorry I wrote wrong value for Win98.
    They should be:

    Windows2000 3~5%,
    Linux2.6 ~25%,
    Windows98se ~100% (it means one of the cores is fully occupied by parallels!).

    I know there are many background processes even in idle state, the cpu usage
    in linux guest indicates 99% idle. So I concluded that parallels does some redundant works
    for linux guest. I wish Parallels team provides some tweaks for this problem.

    Here are the results of top command on the host for different guest OSs. I measured
    just after the first login from a cold boot of guest. I have installed parallels tool for Win2k
    and win98.

    Windows2000:
    PID COMMAND %CPU TIME #TH #PRTS #MREGS RPRVT RSHRD RSIZE VSIZE
    2110 Parallels 0.0% 0:00.00 1 8 101 1.96M 12.1M 644K 92.6M
    2109 Parallels 4.1% 16:14.10 13 214 475 57.3M 639M 185M 1.24G

    Linux2.6:
    PID COMMAND %CPU TIME #TH #PRTS #MREGS RPRVT RSHRD RSIZE VSIZE
    2110 Parallels 0.0% 0:00.00 1 8 101 1.96M 11.0M 644K 92.6M
    2109 Parallels 22.7% 2:56.13 17 182 450 58.1M- 371M 251M- 999M-

    Windows98se:
    PID COMMAND %CPU TIME #TH #PRTS #MREGS RPRVT RSHRD RSIZE VSIZE
    2110 Parallels 0.0% 0:00.00 1 8 101 1.98M 11.7M 644K 92.6M
    2109 Parallels 102.0% 14:02.39 17 207 471 59.2M 213M 103M 1015M

    host:
    MBP 2G, 2Gmem, PW2.1 beta6.
     
  4. drtimhill

    drtimhill Member

    Messages:
    85
    You should flag this as a bug in PW. However, you might also want to look around and see what it is you have running in Win98SE. Anti-virus? Screen-saver? Even innocent tools might have done something bad. Win98 software was generally pretty awful when it came to hogging the cpu.

    --Tim
     
  5. PeterGraf

    PeterGraf Bit poster

    Messages:
    5
    Hello Mimi

    I think this is also a function of the guest operating system running.
    I have Suse 10.0 as a Linux guest on a Mac Mini core duo,
    2 GB ram total, 1 GB ram dedicated to the parallels VM.

    Screenshot: http://www.mission-base.com/peter/screenshot.jpg

    OS X shows a load of about 10%, ( upper and lower right of the screen shot )
    while the Linux guest shows 0% usage. ( upper left of the screen shot )
    10 % loss is not bad, I think, considering that the linux machine is
    fully visible and functioning as a server on my network.

    Greetings!

    Peter
     
  6. constant

    constant Forum Maven

    Messages:
    1,010
    .
    The Windows idle bug was reported and fixed some time back. You will have to do your own searching in forums for that.

    Doing a bug report now for Linux would be the way to go.
    .
     
  7. mimi

    mimi Member

    Messages:
    24
    expect less cpu usage for linux guests

    thank you for some replies.
    I used bare Win98SE without any further installations. I suppose the kernel of Win98 is quite different from that of Win2K/XP. So I would not care about Win98 anymore.
    I know the idle problem in Win2K/XP was discussed sometime ago and then PW team tweaked to solve the problem in beta2~4. Therefore I would expect such tweaks for Linux, too. I think 10% is still not small enough for me.
     
  8. netdog

    netdog Hunter

    Messages:
    117
    As reported in another thread, I am experiencing moderately high core usage when idling in XP Home SP2 guest using Beta 6.
     
  9. mimi

    mimi Member

    Messages:
    24
    same with RC, unfortunately

    The problem still exists in RC, unfortunately.

    Win2K:
    382 Parallels 0.0% 0:00.00 1 8 89 1.92M 18.4M 984K 97.9M
    381 Parallels 4.3% 2:10.47 10 127 398 20.7M 697M 203M 1.12G

    Linux2.6:
    382 Parallels 0.0% 0:00.00 1 8 89 1.94M 19.8M 984K 97.9M
    381 Parallels 28.8% 3:33.20 19 215 481 22.1M 439M 232M 929M

    Win98SE:
    382 Parallels 0.0% 0:00.00 1 8 89 1.94M 19.9M 984K 97.9M
    381 Parallels 102.6% 7:31.88 17 220 473 22.7M 252M 82.3M 929M

    PW2.1 RC B1832, MBP 2G 2Gmem.

    About 30% of CPU usage for Linux guest is preserved even after the completion
    of a shutdown procedure ( till manually "power off" the VM). It seems that the detection
    of HALT status is not perfect.
     
  10. mimi

    mimi Member

    Messages:
    24
    RC2: improved for W98

    Since RC2 is available now, I measured the cpu load again for three OSs.
    As stated in the announcement, the 98% load issue in Win98 has been solved.
    I am still wondering why win2K VM is so light compared with others. Linux VM
    consumes 28% load even after shutdown.


    Win2K:
    327 Parallels 5.1% 1:42.27 12 145 454 23.6M 743M 157M 1.22G

    Win98:
    327 Parallels 27.6% 3:53.74 17 213 495 24.5M 317M 83.8M 1003M

    Linux2.6:
    327 Parallels 27.9% 6:09.07 19 228 514 24.8M 481M- 235M- 1005M-

    Linux2.6: Power-down (VM is running)
    327 Parallels 27.8% 6:43.75 19 228 510 24.8M 481M 236M 1005M

    No VM is running
    327 Parallels 0.5% 7:06.58 4 196 447 23.5M 188M 54.2M 695M


    MBP 2G, 2G-mem, PW 2.1 RC2, 1.2G mem at max. is allocated for PW.
     
  11. mimi

    mimi Member

    Messages:
    24
    GA: still >25% CPU load in idle

    Since GA is available now, I checked CPU loads of three different VM. Unfortunately,
    no improvements from RC2.

    Linux2.6:
    293 Parallels 25.8% 1:48:31 19 209 660 22.8M 320M 215M 995M

    Linux2.6: (Power off)
    293 Parallels 25.8% 1:49:23 19 209 656 22.3M 329M 217M 995M

    Win98:
    293 Parallels 24.1% 1:52:00 17 208 651 22.5M 156M 65.6M 993M

    Win2K:
    293 Parallels 3.7% 1:56:37 13 212 653 14.8M 585M 128M 1.22G
     
  12. MicroDev

    MicroDev Hunter

    Messages:
    122
    That's not been my experience. The GA release seems to have addressed part of the problem. Previously, SMB sharing causing PWS to spin out and pull 10-25% just sitting there. In the GA, it's about 5-10%. If I turn off SMB sharing, it drops to < 5%. This is much better than the RC's but there is still something I can't nail down. PWS also does not release all memory after exit but that's a topic for another thread...

    Don't get me wrong, this is by far better than VPC ever was and I am thoroughly happy with PWS.
     
  13. dwd

    dwd Bit poster

    Messages:
    1
    I'm experiencing the same symptom

    I'm experiencing the same ~25% busy time with the same idle guest OS, Scientific Linux 4.2. Just another datapoint. My system is a Macbook Pro 1.83Ghz, 1GB memory. The guest has 384MB assigned to it.
     

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