From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Mon,  1 Aug 2011 08:36:22 -0400
To: 9fans@9fans.net
Message-ID: <2f1c96759475c0a5e3b8a59eec02d2dc@brasstown.quanstro.net>
In-Reply-To: <9ede6397cd5d6431cfc44a2504cdae6f@swcp.com>
References: <9ede6397cd5d6431cfc44a2504cdae6f@swcp.com>
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Subject: Re: [9fans] nsec limits?
Topicbox-Message-UUID: 09769f42-ead7-11e9-9d60-3106f5b1d025

On Mon Aug  1 08:19:23 EDT 2011, ebo@sandien.com wrote:
>  I am setting up some timing tests and am currently dumping the
>  timestamps using nsec().  When I post-process the data I find that the
>  it is wrapping around, but I have not found anything that clearly states
>  when it does that.  From the code I am guessing that is on the second
>  boundary.  Is that correct?

if nsec(2) is wrapping around then time(2) will also wrap around.
i have not seen nsec do anything like that.  it sounds to me like
you may be having integer truncation problems.  are you using a
(u)vlong variable to store the results of nsec?

- erik

---

; cat > nsec.c
#include <u.h>
#include <libc.h>

void
main(void)
{
	print("%llud\n", nsec());
	sleep(10000);
	print("%llud\n", nsec());
}
<eot>; tmk nsec.c
8c -FVTw nsec.c
8l -o 8.nsec nsec.8
; 8.nsec
1312201920700241540
1312201930703219588
; hoc
(1312201930703219588 - 1312201920700241540)/1e9
10.002978048