On 07/14/2001 12:29:58 PM ZE2 Manuel Bouyer wrote:
>
>On Sat, Jul 14, 2001 at 12:28:25AM +0200, Christian Groessler wrote:
>> On 07/13/2001 11:44:34 PM ZE2 Manuel Bouyer wrote:
>> >
>> >On Fri, Jul 13, 2001 at 11:05:13PM +0200, Christian Groessler wrote:
>> >>
>> >> About every 3 seconds the vmware machine freezes for about 3
>> >> seconds.
>> >> While this happens one of the vmware processes is in a function
>> >> "xscmd".
>> >> Here's the ps axl line:
>> >>
>> >>    0 363  360   0  -6 -19  3092   1992 xscmd    D<L  ?? 0:00.13
>> >>    /emul/linux/usr/local/bin/vmware -q notesnt/vm-nt.cfg
>> >>
>> >> I cannot find this xscmd function, a nm /netbsd | grep xscmd reveils
>> >> nothing.
>> >
>> >This is in the scsipi code. Your process is waiting for a SCSI or ATAPI
>> >command to complete.
>>
>> But why didn't I find the name in /netbsd? I'm still curious where ps
>> got it from.
>
>This isn't a symbol but a string:
>scsipi_base.c:1901:             (void) tsleep(xs, PRIBIO, "xscmd",
>0);

Hmm, I see. But wouldn't it be better, given that this is the only
tsleep in this function, to use the function name as string, instead
of xscmd (which might mean something like "transfer sync. command")?

Or how am I supposed to find the place where the process sleeps short
of a grep over the whole source archive?


>>
>> But, I'm sorry to say, there still seems to be a problem/quirk in NetBSD
>> VMWare. The drive wasn't empty (but the drive is really cheap). It
>> takes this delay when accessing it (mounting and reading data) on both
>> Linux and NetBSD native.
>
>But this doesn't hang the machine, rigth ?

No, only a temporary freeze (~ 3s).

>
>> So this explains the delay. But using the same vmware configuration,
>> running it on Linux this delay (freeze) doesn't happen.
>> Either on Linux these (VMWare/NT4?) device accesses are cached or
>> don't affect the machine this heavily?
>
>I think NT does this to detect when a media is inserted in the CD.
>If linux caches accesses then NT wouldn't be able to detect a media load.
>Maybe in linux vmware does this is a different thread, so that it doesn't
>have to wait for the command to complete to keep running ?

I don't know. At least the number of threads on Linux and NetBSD are
the same.

regards,
chris