Experiences with 7.0-CURRENT and vmware.

Ivan Voras ivoras at fer.hr
Thu May 10 14:52:41 UTC 2007


>>> I should add that FreeBSD 6, with the same setting, is no better and that 
>>> I need to run ntpdate every 5-10 minutes via crontab in order to keep good 
>>> time (timekeeping is *really* bad.)  In one instance, i was watching 
>>> "zpool iostat 1" and it appeared like the rows were muching up at a rate 
>>> of 2 a second for a minute or so. How do I disable TSC timekeeping?  
>>> (NetBSD has this disabled by default in their kernels.)  Or is there 
>>> somethign else I must do?
>> kern.timecounter.hardware: ACPI-fast
>> kern.timecounter.choice: TSC(800) ACPI-fast(1000) i8254(0) dummy(-1000000)

I don't see the beginings of this disucssion, but, if you use TSC 
timekeeping in guest, and the host is multicore (may also be valid for 
multi-socket...) running Windows, the Windows scheduler will throw the 
vmware process around on the CPUs, giving weird measurements in the 
guest machine. The solution is to bind the vmware-vmx process in the 
Windows task manager to one CPU only. Using this, I get what appears to 
be "reasonable" timekeeping (didn't really fiddle with it more, but I 
run ntpd).

I also run on a very low kern.hz (50), this may or may not make a big 
difference.

>>> Second, networking. Prior to FreeBSD-7, the driver to use inside vmware 
>>> workstation was lnc.  It has worked and contiues to work great.  No 
>>> problemo. FreeBSD-7 uses the "em" driver.  To put it simply, it sucks in 
>>> comparison.  When things really get bad I start seeing "em0: watchdog 
>>> timeout" messages on the console.  I looked and I don't see a lnc driver 
>>> anywhere.  Is there another alternative (le?) driver that I can use in 
>>> place of em, if so, how?
>> Has VMware changed what network hardware they emulate, and/or does VMware 
>> offer options about what virtual hardware to expose?

Recent VMWare versions can emulate either AMD Lance (or its variation, 
it appears, called vix) or Intel "E1000" card. See, for example, my 
writing on this: http://ivoras.net/freebsd/vmware.html.

In retrospect, I think I can't really say there's a difference in 
performance between le and em drivers in VMWare - other slowdowns 
dominate the results.

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