Problem with time.time() standing still

[Cameron Simpson]

On 06May2012 09:18, Bob Cowdery <bob at bobcowdery.plus.com> wrote:
| On 05/05/2012 23:05, Cameron Simpson wrote:
| > On 05May2012 20:33, Bob Cowdery <bob at bobcowdery.plus.com> wrote:
| > | [...] calls to time.time() always return the same
| > | time which is usually several seconds in the past or future and always
| > | has no fractional part.
| >
| > Thought #1: you are calling time.time() and haven't unfortunately
| > renamed it? (I doubt this scenario, though the lack of fractional part
| > is interesting.)
|
| Not sure what you mean by renamed it.

Like this:

  from time import time
  [...]
  time = some_unfortunate_other_function
  [...]
  now = time()  # calls wrong function

It seems unlikely, but possible.

| I also tried datetime and that had
| the same behaviour.

Makes my suggestion even less likely unless the time module itself gets
monkeypatched (i.e. "time.time = bad_function" somewhere).

| > | If I leave it long enough time will suddently
| > | jump forward after a few minutes, then again after a few minutes more.
| > | 
| > | I've never encountered this behaviour before and can't understand what
| > | on earth is going on. If I call the 'C' time() function just the other
| > | side of my call to the extension the time is ticking along fine. It's
| > | just the one Python thread that is affected.
| > [...]
| >
| > Thought #2: On a UNIX system I'd be running the process under strace (or
| > dtrace or ktrace depending on flavour) to see what actual OS system calls are
| > being made during this behaviour. Is this feasible for you?
|
| I'm on Windows for this particular part of the application.

I'd guessed so. I've no Windows programming background; I was wondering
if there was something like this you had to hand on windows.

| [...] But debugging into this is probably the only way. I
| looked at the built-in time module. As far as I can tell it just calls
| the underlying C time() function as an extension. This is more
| mystifying as that is pretty much what I'm doing by checking the time in
| my own extension module where it ticks along fine.

Hmm. A C extension I presume? How about writing a little pure Python
thread to call time.time(), and spin it off parallel to the rest of the
app; does it also get bad time.time() behaviour?

| I have another
| scenario using a different part of their SDK where the time does still
| tick but the fractional part is frozen, not 0 but frozen.

Curiouser and curiouser.
-- 
Cameron Simpson <cs at zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

As you can see, unraveling even a small part of 'sendmail' can introduce more
complexity than answers.        - Brian Costales, _sendmail_