From: Christian Krafft <parabelboi@bopserverein.de>
To: Carl Love <cel@us.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
oprofile-list@lists.sourceforge.net, cbe-oss-dev@ozlabs.org
Subject: Re: [Cbe-oss-dev] [RFC, PATCH 4/4] Add support to OProfile for profiling Cell BE SPUs -- update
Date: Wed, 31 Jan 2007 12:25:33 +1100 [thread overview]
Message-ID: <20070131122533.5ef22907@localhost> (raw)
In-Reply-To: <1170199869.5235.38.camel@dyn9047021078.beaverton.ibm.com>
On Tue, 30 Jan 2007 15:31:09 -0800
Carl Love <cel@us.ibm.com> wrote:
> An LFSR sequence is similar to a pseudo random number sequence. For a 24
> bit LFSR sequence each number between 0 and 2^24 will occur once in the
> sequence but not in a normal counting order. The hardware uses the LFSR
> sequence to count to since it is much simpler to implement in hardware
> then a normal counter. Unfortunately, the only way we know how to
> figure out what the LFSR value that corresponds to the number in the
> sequence that is N before the last value (0xFFFFFF) is to calculate the
> previous value N times. It is like trying to ask what is the pseudo
> random number that is N before this pseudo random number?
That should be no problem.=20
You can just revers your algorithm and let it run x times instead of 0xFFFF=
FF-x.
>=20
> I will add a short comment to the code that will summarize the above
> paragraph.
> [snip]
>=20
> _______________________________________________
> cbe-oss-dev mailing list
> cbe-oss-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/cbe-oss-dev
--=20
Mit freundlichen Gr=FCssen,
kind regards,
Christian Krafft
IBM Systems & Technology Group,=20
Linux Kernel Development
IT Specialist
WARNING: multiple messages have this Message-ID (diff)
From: Christian Krafft <parabelboi@bopserverein.de>
To: Carl Love <cel@us.ibm.com>
Cc: maynardj@us.ibm.com, linuxppc-dev@ozlabs.org,
oprofile-list@lists.sourceforge.net, cbe-oss-dev@ozlabs.org,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [Cbe-oss-dev] [RFC, PATCH 4/4] Add support to OProfile for profiling Cell BE SPUs -- update
Date: Wed, 31 Jan 2007 12:25:33 +1100 [thread overview]
Message-ID: <20070131122533.5ef22907@localhost> (raw)
In-Reply-To: <1170199869.5235.38.camel@dyn9047021078.beaverton.ibm.com>
On Tue, 30 Jan 2007 15:31:09 -0800
Carl Love <cel@us.ibm.com> wrote:
> An LFSR sequence is similar to a pseudo random number sequence. For a 24
> bit LFSR sequence each number between 0 and 2^24 will occur once in the
> sequence but not in a normal counting order. The hardware uses the LFSR
> sequence to count to since it is much simpler to implement in hardware
> then a normal counter. Unfortunately, the only way we know how to
> figure out what the LFSR value that corresponds to the number in the
> sequence that is N before the last value (0xFFFFFF) is to calculate the
> previous value N times. It is like trying to ask what is the pseudo
> random number that is N before this pseudo random number?
That should be no problem.
You can just revers your algorithm and let it run x times instead of 0xFFFFFF-x.
>
> I will add a short comment to the code that will summarize the above
> paragraph.
> [snip]
>
> _______________________________________________
> cbe-oss-dev mailing list
> cbe-oss-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/cbe-oss-dev
--
Mit freundlichen Grüssen,
kind regards,
Christian Krafft
IBM Systems & Technology Group,
Linux Kernel Development
IT Specialist
next prev parent reply other threads:[~2007-01-31 1:25 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-29 19:45 [RFC, PATCH 0/4] Add support to OProfile for profiling Cell BE SPUs -- update Maynard Johnson
2007-01-29 19:46 ` [RFC, PATCH 1/4] " Maynard Johnson
2007-01-30 4:07 ` [Cbe-oss-dev] " Arnd Bergmann
2007-01-30 4:07 ` Arnd Bergmann
2007-01-30 10:39 ` Christoph Hellwig
2007-01-30 10:39 ` Christoph Hellwig
2007-01-30 22:49 ` Carl Love
2007-01-30 22:49 ` Carl Love
2007-01-30 22:57 ` Benjamin Herrenschmidt
2007-01-30 22:57 ` Benjamin Herrenschmidt
2007-01-31 8:47 ` Christoph Hellwig
2007-01-31 8:47 ` Christoph Hellwig
2007-01-30 22:59 ` Benjamin Herrenschmidt
2007-01-30 22:59 ` Benjamin Herrenschmidt
2007-01-29 19:47 ` [RFC, PATCH 2/4] " Maynard Johnson
2007-01-30 4:08 ` [Cbe-oss-dev] " Arnd Bergmann
2007-01-30 4:08 ` Arnd Bergmann
2007-01-30 23:51 ` Carl Love
2007-01-30 23:51 ` Carl Love
2007-01-29 19:48 ` [RFC, PATCH 3/4] " Maynard Johnson
2007-01-30 4:24 ` [Cbe-oss-dev] " Arnd Bergmann
2007-01-30 4:24 ` Arnd Bergmann
2007-01-30 15:31 ` Maynard Johnson
2007-01-30 15:31 ` Maynard Johnson
2007-01-31 0:35 ` Arnd Bergmann
2007-01-31 0:35 ` Arnd Bergmann
2007-01-29 19:48 ` [RFC, PATCH 4/4] " Maynard Johnson
2007-01-30 7:39 ` [Cbe-oss-dev] " Arnd Bergmann
2007-01-30 7:53 ` Benjamin Herrenschmidt
2007-01-30 7:53 ` Benjamin Herrenschmidt
2007-01-30 10:41 ` Christoph Hellwig
2007-01-30 10:41 ` Christoph Hellwig
2007-01-30 23:09 ` Maynard Johnson
2007-01-30 23:09 ` Maynard Johnson
2007-01-30 21:41 ` Maynard Johnson
2007-01-30 21:41 ` Maynard Johnson
2007-01-30 22:54 ` Maynard Johnson
2007-01-30 22:54 ` Maynard Johnson
2007-01-30 23:34 ` Benjamin Herrenschmidt
2007-01-30 23:34 ` Benjamin Herrenschmidt
2007-01-31 0:29 ` Maynard Johnson
2007-01-31 0:29 ` Maynard Johnson
2007-01-31 6:52 ` Arnd Bergmann
2007-01-31 6:52 ` Arnd Bergmann
2007-02-02 16:47 ` Maynard Johnson
2007-02-02 16:47 ` Maynard Johnson
2007-02-03 7:40 ` Arnd Bergmann
2007-02-03 7:40 ` Arnd Bergmann
2007-02-03 20:03 ` Maynard Johnson
2007-02-03 20:03 ` Maynard Johnson
2007-02-04 2:42 ` Arnd Bergmann
2007-02-04 2:42 ` Arnd Bergmann
2007-02-04 17:11 ` Maynard Johnson
2007-02-04 17:11 ` Maynard Johnson
2007-01-30 23:31 ` Carl Love
2007-01-30 23:31 ` Carl Love
2007-01-31 1:25 ` Christian Krafft [this message]
2007-01-31 1:25 ` Christian Krafft
2007-01-31 6:06 ` Arnd Bergmann
2007-01-31 6:06 ` Arnd Bergmann
2007-01-31 5:57 ` Arnd Bergmann
2007-01-31 5:57 ` Arnd Bergmann
2007-02-02 19:27 ` Maynard Johnson
2007-02-02 19:27 ` Maynard Johnson
2007-02-03 23:49 ` Maynard Johnson
2007-02-03 23:49 ` Maynard Johnson
2007-02-04 2:52 ` Arnd Bergmann
2007-02-04 2:52 ` Arnd Bergmann
2007-02-04 17:33 ` Maynard Johnson
2007-02-04 17:33 ` Maynard Johnson
2007-01-31 9:24 ` Milton Miller
2007-01-31 15:42 ` Arnd Bergmann
2007-02-01 18:56 ` Milton Miller
2007-02-02 0:54 ` Arnd Bergmann
2007-01-30 8:37 ` [RFC, PATCH 0/4] " Arnd Bergmann
2007-01-30 8:37 ` Arnd Bergmann
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