From: Der Herr Hofrat <der.herr@mail.hofr.at>
To: "Serguei I. Ivantsov" <administrator@svitonline.com>
Cc: linux-gcc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Measure time
Date: Wed, 8 May 2002 14:00:36 +0200 (CEST) [thread overview]
Message-ID: <200205081200.g48C0a805476@hofr.at> (raw)
In-Reply-To: <abaokj$ugl$1@news.lucky.net> from "Serguei I. Ivantsov" at "May 8, 2002 11:48:24 am"
> Hello!
>
> Is there any function for high precision time measuring.
> time() returns only in second. I need nanoseconds.
>
you can directly read the TSC but that will not realy give you nanoseconds
resolution as the actual read access even on a PIII/1GHz is going to take
up to a few 100 nanoseconds, and depending on what you want to time
stamp the overall jitter of that code can easaly be in the
range of a microsecond.
There are some hard-realtime patches to the Linux kernel that will
allow time precission of aprox. 1us (the TSC has a precission of 32ns)
but I don't think you can get below that without dedicated hardware.
for RTLinux check at ftp://ftp.rtlinux.org/pub/rtlinux/
hofrat
next prev parent reply other threads:[~2002-05-08 12:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-08 8:48 Measure time Serguei I. Ivantsov
2002-05-08 12:00 ` Der Herr Hofrat [this message]
2002-05-08 15:46 ` Serguei I. Ivantsov
2002-05-08 16:25 ` Nate
2002-05-08 16:40 ` george anzinger
2002-05-08 16:51 ` Simon Butcher
2002-05-08 16:58 ` Der Herr Hofrat
2002-05-08 23:22 ` george anzinger
2002-05-08 16:26 ` Calin A. Culianu
2002-05-08 12:21 ` Richard B. Johnson
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