[9fans] more time amusement under vmware

[9fans] more time amusement under vmware

[roger peppe]

the time problem i was having before (fast clock) had seemed to be
irreproducible. however just now, i noticed the following
odd behaviour:

fiddle% date -u
Thu Jan  1 00:00:00 GMT 1970
fiddle% cat /dev/time
          0                     0                     0
     1 fiddle%
fiddle% # wait a few seconds
fiddle% cat /dev/time
          0                     0                     0
     1 fiddle%

the clock is completely stopped!
(although sleep doesn't sleep forever - sleep 10 sleeps
for about 3.43 seconds, so *something* has a concept of time)

most odd.

Re: [9fans] more time amusement under vmware

[David Leimbach]

[-- Attachment #1: Type: text/plain, Size: 770 bytes --]

On Mon, Aug 3, 2009 at 10:56 PM, roger peppe <rogpeppe@gmail.com> wrote:

> the time problem i was having before (fast clock) had seemed to be
> irreproducible. however just now, i noticed the following
> odd behaviour:
>
> fiddle% date -u
> Thu Jan  1 00:00:00 GMT 1970
> fiddle% cat /dev/time
>          0                     0                     0
>     1 fiddle%
> fiddle% # wait a few seconds
> fiddle% cat /dev/time
>          0                     0                     0
>     1 fiddle%
>
> the clock is completely stopped!
> (although sleep doesn't sleep forever - sleep 10 sleeps
> for about 3.43 seconds, so *something* has a concept of time)
>
> most odd.
>
>

Yeah.. :-(  Odd and crappy.  I can't figure out why this would happen.

[-- Attachment #2: Type: text/html, Size: 1077 bytes --]

Re: [9fans] more time amusement under vmware

[erik quanstrom]

> fiddle% date -u
> Thu Jan  1 00:00:00 GMT 1970
> fiddle% cat /dev/time
>           0                     0                     0
>      1 fiddle%
> fiddle% # wait a few seconds
> fiddle% cat /dev/time
>           0                     0                     0
>      1 fiddle%

what's especially wrong about this is that /bin/time is supposed
to have 4 fields:

; cat /dev/time;echo
 1249390400   1249390400255704909     10724776694552845            2000102324
;

do you have something funny bound on /dev?

- erik

Re: [9fans] more time amusement under vmware

[roger peppe]

2009/8/4 erik quanstrom <quanstro@quanstro.net>:
>> fiddle% cat /dev/time
>>           0                     0                     0
>>      1 fiddle%
> what's especially wrong about this is that /bin/time is supposed
> to have 4 fields:

it does - it just that the line wrapped.
the value of the last field is 1.

Re: [9fans] more time amusement under vmware

[roger peppe]

2009/8/4 erik quanstrom <quanstro@quanstro.net>:
> do you have something funny bound on /dev?

having said what i said - yes, i realise that a mistaken
bind -b means that i was using drawterm's /dev/time,
not the host system's.

and, oddly, drawterm implements the time
file, but doesn't bother to actually get the correct time
of day.

so not as strange as i thought. cheers erik.

Re: [9fans] more time amusement under vmware

[ron minnich]

This is the same kind of problem I had under Xen in the beginning. The
fix is to figure out what vmware gives you in the way of time info and
use that exclusively.

It problem seems odd but you can have cases where, e.g., 'sleep 10'
works and date is not right. I had this under both lguest and xen.

It's been enough years that I have forgotten but you also want to stop
using the emulated pc-style timer interrupts. It's clear that vmware
is not exactly getting these right.

A look at the xen port might give some hints.

Just figure out if vmware gives you a nice "time of universe" 64-bit
counter or something and take your time from that.

Or, alternatively, stop using vmware :-) That strikes me as the best bet.

ron

Re: [9fans] more time amusement under vmware

[ron minnich]

On Tue, Aug 4, 2009 at 8:20 AM, ron minnich<rminnich@gmail.com> wrote:

> It problem
       probably

sorry

ron