linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Paul Mackerras <paulus@samba.org>
To: Gabriel Paubert <paubert@iram.es>
Cc: Chris Friesen <cfriesen@nortelnetworks.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] (comments requested) adding finer-grained timing to PPC add_timer_randomness()
Date: Thu, 23 Aug 2001 22:31:20 +1000 (EST)	[thread overview]
Message-ID: <15236.63384.489975.150804@cargo.ozlabs.ibm.com> (raw)
In-Reply-To: <Pine.LNX.4.21.0108231137080.2015-100000@ltgp.iram.es>
In-Reply-To: <15236.23943.260421.31691@cargo.ozlabs.ibm.com> <Pine.LNX.4.21.0108231137080.2015-100000@ltgp.iram.es>

Gabriel Paubert writes:

> Reading the PVR is probably faster in this case, since you avoid a
> potential cache miss.

Yep.

> As I said in an earlier message the __USE_RTC macro
> should be made dependent on whether the kernel supports 601 or not.

We don't have USE_RTC in 2.2.  The proposed patch was for 2.2.19.

> No, this is not what they are trying to capture. Furthermore the 7 LSB of
> the decrementer on a 601 are not random (but they don't seem to be 0
> always despite the documentation) so you would have to shift the result

Don't you mean that the 7 LSB of RTCL aren't random and are supposed
to be 0?  The decrementer should decrement by 1 at a rate of 7.8125MHz
and all the bits should be implemented.

Paul.

  parent reply	other threads:[~2001-08-23 12:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-08-22 20:57 [PATCH] (comments requested) adding finer-grained timing to PPC add_timer_randomness() Chris Friesen
2001-08-22 21:06 ` Ignacio Vazquez-Abrams
2001-08-22 21:27   ` Chris Friesen
2001-08-23  1:33   ` Paul Mackerras
2001-08-23  9:46     ` Gabriel Paubert
2001-08-23 13:11       ` Benjamin Herrenschmidt
2001-08-23 12:31     ` Paul Mackerras [this message]
2001-08-24  7:32       ` Gabriel Paubert
2001-08-24 13:59         ` Christopher Friesen
2001-08-28 20:50           ` Gabriel Paubert
2001-08-24 17:54         ` [PATCH] (comments requested) adding finer-grained timing to PPC Albert D. Cahalan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=15236.63384.489975.150804@cargo.ozlabs.ibm.com \
    --to=paulus@samba.org \
    --cc=cfriesen@nortelnetworks.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=paubert@iram.es \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).