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Explanation of Performance monitor graphs
Posted: 28. May 2022, 18:26
by descott12
Hello,
I am running VB 6.1.34 on a Windows 10 Pro host. Everything is working amazingly well with my XP and Win7 guests. Guest Additions installed, acceleration is enabled and seems to be working well. My question is regarding the performance donut graph.
Usually, my guest load is 50% and my VMM load is around 3 to 4%. What do those actually mean? It appears that I am not using all the CPU/resources available so I am hoping I can decrease some long compile times by tweaking something.
Thanks in advance for any pointers. The user guide is very well written but seems to have skipped this topic.
Re: Explanation ofPerformance monitor graphs
Posted: 28. May 2022, 21:37
by fth0
Please provide a (zipped) VBox.log file from a complete VM run: Start a VM, run a compilation task for at least 15 minutes and shut down the VM from inside the guest OS. Afterwards, I'll try and explain some of the CPU statistics which relate to your question.
Re: Explanation ofPerformance monitor graphs
Posted: 28. May 2022, 23:40
by descott12
Here you go. The compile seemed to go a bit faster so not sure if it ran for a full 15 minutes.
Thanks alot for looking at this.
Re: Explanation ofPerformance monitor graphs
Posted: 29. May 2022, 01:14
by fth0
descott12 wrote:The compile seemed to go a bit faster so not sure if it ran for a full 15 minutes.
It wasn't that important.
The main idea behind my request was that the majority of VM runtime was used for the compilation, so that the VM statistics roughly correspond to that period of time. Let's have a look at some larger numbers (disk I/O and CPU load):
WinXP-2022-05-28-17-37-20.log wrote:00:13:08.043486 /Public/Storage/PIIX3IDE0/Port0/BytesRead 508,717,056 bytes
00:13:08.043488 /Public/Storage/PIIX3IDE0/Port0/BytesWritten 1,635,636,224 bytes
00:13:08.043495 /Public/Storage/PIIX3IDE0/Port0/ReqsRead 22,234 count
00:13:08.043502 /Public/Storage/PIIX3IDE0/Port0/ReqsWrite 79,881 count
~22k read requests and ~80k write requests give an impression of the amount of disk I/O involved.
WinXP-2022-05-28-17-37-20.log wrote:00:13:08.043524 /TM/CPU/00/cNsExecuting 402,709,901,262 ns
00:13:08.043526 /TM/CPU/00/cNsHalted 349,699,481,180 ns
00:13:08.043529 /TM/CPU/00/cNsOther 32,556,659,002 ns
00:13:08.043531 /TM/CPU/00/cNsTotal 784,966,041,444 ns
00:13:08.043534 /TM/CPU/00/cPeriodsExecuting 11,561,453 count
00:13:08.043536 /TM/CPU/00/cPeriodsHalted 524,111 count
00:13:08.043545 /TM/CPU/01/cNsExecuting 251,822,488,811 ns
00:13:08.043547 /TM/CPU/01/cNsHalted 502,072,024,318 ns
00:13:08.043550 /TM/CPU/01/cNsOther 30,591,093,093 ns
00:13:08.043552 /TM/CPU/01/cNsTotal 784,485,606,222 ns
00:13:08.043554 /TM/CPU/01/cPeriodsExecuting 12,827,028 count
00:13:08.043556 /TM/CPU/01/cPeriodsHalted 716,417 count
In the VM statistics for the 2 vCPUs that you've provided to the VM,
cNsTotal accumulated the total runtime of ~785 seconds.
cNsExecuting accumulated the time when the vCPUs were executing guest code and using host CPU cycles, which was ~1/2 of the time for vCPU0 and ~1/3 of the time for vCPU1.
cNsHalted accumulated the time when the vCPUs were halted and not taking host CPU cycles, which was ~1/2 of the time for vCPU0 and ~2/3 of the time for vCPU1.
cNsOther accumulated the time when the VirtualBox
VMM (Virtual Machine Monitor) executed some code on behalf of the guest, which was less than 5% of the time for both vCPUs (*).
I didn't notice anything unusual in the log file. In general, compilation with many small files can be I/O bound. I'd suggest to use your favorite task manager inside the guest OS to investigate further. Additionally, you could clone the VM and convert the virtual hard disk to the VDI format, which is perhaps implemented more efficiently. Let us know what you discover ...
(*) Regarding the VirtualBox
Performance Monitor,
Guest Load corresponds to
cNsExecuting/cNsTotal and
VMM Load corresponds to
cNsOther/cNsTotal.
Re: Explanation ofPerformance monitor graphs
Posted: 29. May 2022, 02:39
by descott12
Thank you and you explained what the VMM was. That was unclear. Oddly, the compiles seem quite speedy now. For some reason when I first got the VM running, they were about 2x slower. So really I think my problem is solved.
Cheers.
Re: Explanation ofPerformance monitor graphs
Posted: 29. May 2022, 10:58
by mpack
If the VMs were brand new (AFAICS you did not say), then it's a common symptom of brand new Windows installs that they spend a lot of time doing self checks, update checks, etc. We often recommend just leaving the VM running all night to allow everything to settle down.
Re: Explanation ofPerformance monitor graphs
Posted: 31. May 2022, 00:36
by descott12
The VMs were very old and I had transferred them from Parallels on a mac laptop. All seems to be very snappy now so not sure what that was all about.
Thanks