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Date:      Thu, 04 Jun 1998 08:51:53 +0200
From:      Poul-Henning Kamp <phk@critter.freebsd.dk>
To:        "Richard S. Straka" <straka@home.com>
Cc:        current@FreeBSD.ORG
Subject:   Re: strange behavior with signal latencies 
Message-ID:  <14707.896943113@critter.freebsd.dk>
In-Reply-To: Your message of "Wed, 03 Jun 1998 22:56:51 PDT." <35763722.C34EEF4E@home.com> 

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In message <35763722.C34EEF4E@home.com>, "Richard S. Straka" writes:
>I wrote a small test program to look at latencies of user space
>processes waking up on  the delivery of signals.

Hi Richard,

This is very interesting work.  The time keeping code in -current
is entirely new, so it is not a given that it is actually a latency,
it could be a genuine bug...

A few pointers:

1. Use clock_gettime(2) on -current, then you get nanoseconds (-stable
   cannot do that, it will just give you microseconds * 1000).

2. Do you have ntpd enabled on either machine ?

3. Try to do the "/dev/io" trick and wiggle a line on your printerport
   and then use a 'scope or counter to verify your data.


--
Poul-Henning Kamp             FreeBSD coreteam member
phk@FreeBSD.ORG               "Real hackers run -current on their laptop."
"ttyv0" -- What UNIX calls a $20K state-of-the-art, 3D, hi-res color terminal

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