What is wall clock time? the standard doesn't define it
but I see its use in past posts on clc.
--
aegis
but I see its use in past posts on clc.
--
aegis
-
-
Re: wall clock time
aegis <aegis@mad.scie ntist.com> wrote:[color=blue]
> What is wall clock time? the standard doesn't define it
> but I see its use in past posts on clc.[/color]
Well its the time that your clock on the wall shows.
There need not be any tool, function or else that provides
your C programs with this information, system specific extensions make
make this available.
--
Z (zoran.cutura@w eb.de)
"LISP is worth learning for the profound enlightenment experience
you will have when you finally get it; that experience will make you
a better programmer for the rest of your days." -- Eric S. Raymond
-
Re: wall clock time
"aegis" <aegis@mad.scie ntist.com> wrote in message
news:1103128027 .639830.20420@c 13g2000cwb.goog legroups.com...[color=blue]
> What is wall clock time?[/color]
I don't know of any standardized meaning for it, but
I'd guess it means 'local time'.
[color=blue]
> the standard doesn't define it[/color]
Nope.
[color=blue]
> but I see its use in past posts on clc.[/color]
Perhaps if you give context, we could figure out
what the poster(s) meant.
-Mike
Comment
-
Re: wall clock time
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
aegis wrote:[color=blue]
> What is wall clock time? the standard doesn't define it
> but I see its use in past posts on clc.[/color]
The term "Wall clock time" refers to the elapsed time that an activity
takes, and alludes to the method of timing such an activity: look at the
wall clock when the activity starts, look again when the activity ends,
compute the difference between the two times.
We use this term in contrast to "cpu time", which measures the elapsed
time that an activity takes, excluding all the time the computer is not
performing tasks for that activity (i.e. "data entry" time, etc.).
- --
Lew Pitcher, IT Consultant, Enterprise Data Systems
Enterprise Technology Solutions, TD Bank Financial Group
(Opinions expressed here are my own, not my employer's)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (MingW32)
iD8DBQFBwGpJagV FX4UWr64RArLiAJ 9uccuWUUunxNjj2 +E9gC6loQ2PYgCg yXrp
6NlJdyt4BbThfSQ 9yQvEvw4=
=5AOQ
-----END PGP SIGNATURE-----
Comment
-
Re: wall clock time
>What is wall clock time? the standard doesn't define it[color=blue]
>but I see its use in past posts on clc.[/color]
The time according to a clock on a nearby wall, presuming it is
properly set. This clock would be set according to the local time
zone, and local daylight savings time conventions (if any). WHOSE
wall may be an issue if the user and the system are in different
time zones. A wall clock runs continuously, as distinguished from
a stopwatch.
A Football Game Clock runs only when plays are actually in progress,
and not during timeouts and between plays. A CPU time clock runs
only when the program is using the CPU. When a program is "using
the CPU" is a bit system-specific, but on a multi-tasking system
this generally does not include times the program is waiting for
input, is waiting for disk I/O, paging, or swapping, or is not
scheduled due to other programs running.
Gordon L. Burditt
Comment
-
Re: wall clock time
"aegis"[color=blue]
> What is wall clock time? the standard doesn't define it
> but I see its use in past posts on clc.[/color]
At the risk of making the same error twice in a day, I think wall clock time
is OT as only the difference in time can be handled by C. Otherwise you're
making a system call. If you stipulate any particular t1 then wall clock
time is within the scope of ISO C. MPJ
Comment
-
Re: wall clock time
In article <TPCdnfruz9joEF 3cRVn-iw@comcast.com> ,
Merrill & Michele <beckjensen@com cast.net> wrote:
[color=blue]
> At the risk of making the same error twice in a day, I think wall clock time
> is OT as only the difference in time can be handled by C.[/color]
What about the standard C function time()?
[color=blue]
> Otherwise you're
> making a system call.[/color]
Why is a "system call" used by time() different than a "system call"
used by printf()? A standard C function may, or may not, do one or
more "system calls" but that is up to the implementation, i.e. it is
outside of the standard.
--
Göran Larsson http://www.mitt-eget.com/
Comment
-
Re: wall clock time
Zoran Cutura <zoran.cutura@w eb.de> writes:[color=blue]
> aegis <aegis@mad.scie ntist.com> wrote:[color=green]
>> What is wall clock time? the standard doesn't define it
>> but I see its use in past posts on clc.[/color]
>
> Well its the time that your clock on the wall shows.
> There need not be any tool, function or else that provides
> your C programs with this information, system specific extensions make
> make this available.[/color]
See <time.h>. The time() function gives you a representation of what
I'd refer to as "wall clock time" (as distinct from CPU time).
I suppose "wall clock time" could refer either to a given moment or to
an elapsed time; the latter can be computed by calling difftime().
No system specific extensions are necessary, unless you need some
particular resolution -- or unless you're using the phrase "wall clock
time" to refer to something other than what I'm thinking of.
--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.
Comment
-
Re: wall clock time
On Wed, 15 Dec 2004 13:16:20 -0600, Merrill & Michele wrote:
[color=blue]
>
> "aegis"[color=green]
>> What is wall clock time? the standard doesn't define it
>> but I see its use in past posts on clc.[/color]
>
> At the risk of making the same error twice in a day, I think wall clock time
> is OT as only the difference in time can be handled by C. Otherwise you're
> making a system call. If you stipulate any particular t1 then wall clock
> time is within the scope of ISO C. MPJ[/color]
Wall clock time usually refers to time intervals. E.g. a program was
running for 10 seconds and used 4 seconds of CPU time. The 10 seconds
there is wall clock time, the 4 seconds isn't.
Lawrence
Comment
-
Re: wall clock time
[color=blue]
> "Lawrence Kirby"[color=green]
> > Merrill & Michele wrote:[/color]
>[color=green]
> >
> > "aegis"[color=darkred]
> >> What is wall clock time? the standard doesn't define it
> >> but I see its use in past posts on clc.[/color]
> >
> > At the risk of making the same error twice in a day, I think wall clock[/color][/color]
time[color=blue][color=green]
> > is OT as only the difference in time can be handled by C. Otherwise[/color][/color]
you're[color=blue][color=green]
> > making a system call. If you stipulate any particular t1 then wall[/color][/color]
clock[color=blue][color=green]
> > time is within the scope of ISO C. MPJ[/color]
>
>
> Wall clock time usually refers to time intervals. E.g. a program was
> running for 10 seconds and used 4 seconds of CPU time. The 10 seconds
> there is wall clock time, the 4 seconds isn't.[/color]
What chapter is that in C Unleashed (you guys didn't do the greatest job of
indexing. You did the bitshift stuff and I think a couple more, but the
only way for me to really find anything in that book is sit down and slog
through 400 pages. Maybe a cleaner presentation in version 2?)? MPJ
Comment
-
Re: wall clock time
On Thu, 16 Dec 2004 12:03:03 -0600, Merrill & Michele wrote:
....
[color=blue]
> What chapter is that in C Unleashed (you guys didn't do the greatest job of
> indexing. You did the bitshift stuff and I think a couple more, but the
> only way for me to really find anything in that book is sit down and slog
> through 400 pages. Maybe a cleaner presentation in version 2?)? MPJ[/color]
Well chapter 4 is about times and dates. I don't remember offhand if "wall
clock time" is mentioned specifically. It could have been but it isn't a
term that relates specifically to C.
I'm sure the indexing could be improved, but don't forget the chapter list
at the start. I don't see the need to slog through 400 pages to find
relevant sections. :-)
Lawrence
Comment
-
Re: wall clock time
"Lawrence Kirby"[color=blue]
> Merrill & Michele wrote:
>
> ...
>[color=green]
> > What chapter is that in C Unleashed (you guys didn't do the greatest job[/color][/color]
of[color=blue][color=green]
> > indexing. You did the bitshift stuff and I think a couple more, but the
> > only way for me to really find anything in that book is sit down and[/color][/color]
slog[color=blue][color=green]
> > through 400 pages. Maybe a cleaner presentation in version 2?)? MPJ[/color]
>
> Well chapter 4 is about times and dates. I don't remember offhand if "wall
> clock time" is mentioned specifically. It could have been but it isn't a
> term that relates specifically to C.
>
> I'm sure the indexing could be improved, but don't forget the chapter list
> at the start. I don't see the need to slog through 400 pages to find
> relevant sections. :-)[/color]
The whole point of a reference text is that you HAVE FORGOTTEN the contents.
Merry Christmas, Lawrence. If you talk to Mr. Heathfield, tell him that C
dreams. MPJ
Comment
-
Re: wall clock time
Merrill & Michele wrote:[color=blue]
> "Lawrence Kirby"
>[color=green]
>>Well chapter 4 is about times and dates. I don't remember offhand if "wall
>>clock time" is mentioned specifically. It could have been but it isn't a
>>term that relates specifically to C.[/color][/color]
It gets a passing mention on page 123, as a cursory inspection of the
relevant chapter will reveal. I found it from scratch in about eight
seconds, so it was no real hardship that the term didn't appear in the
index.
[color=blue][color=green]
>>
>>I'm sure the indexing could be improved, but don't forget the chapter list
>>at the start. I don't see the need to slog through 400 pages to find
>>relevant sections. :-)[/color]
>
>
> The whole point of a reference text is that you HAVE FORGOTTEN the contents.[/color]
"C Unleashed" is not a reference text.
Comment
Comment