From: Preeti U Murthy <preeti@linux•vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: peterz@infradead•org, fweisbec@gmail•com,
paul.gortmaker@windriver•com, paulus@samba•org, mingo@kernel•org,
shangw@linux•vnet.ibm.com, rafael.j.wysocki@intel•com,
paulmck@linux•vnet.ibm.com, arnd@arndb•de,
linux-pm@vger•kernel.org, rostedt@goodmis•org,
michael@ellerman•id.au, john.stultz@linaro•org,
tglx@linutronix•de, chenhui.zhao@freescale•com,
deepthi@linux•vnet.ibm.com, r58472@freescale•com,
geoff@infradead•org, linux-kernel@vger•kernel.org,
srivatsa.bhat@linux•vnet.ibm.com, schwidefsky@de•ibm.com,
linuxppc-dev@lists•ozlabs.org
Subject: Re: [RFC PATCH] time: Support in tick broadcast framework for archs without an external wakeup source
Date: Fri, 13 Dec 2013 10:51:23 +0530 [thread overview]
Message-ID: <52AA9953.9090909@linux.vnet.ibm.com> (raw)
In-Reply-To: <1386911862.15730.81.camel@pasglop>
Hi Ben,
On 12/13/2013 10:47 AM, Benjamin Herrenschmidt wrote:
> On Fri, 2013-12-13 at 09:49 +0530, Preeti U Murthy wrote:
>> On some architectures, in certain CPU deep idle states the local timers stop.
>> An external clock device is used to wakeup these CPUs. The kernel support for the
>> wakeup of these CPUs is provided by the tick broadcast framework by using the
>> external clock device as the wakeup source.
>
>> However on architectures like PowerPC there is no external clock device.
>
> Minor nit ...
>
> I wouldn't make this an architectural statement. Some PowerPC's do have
> external clock devices (for example the old MPIC interrupt controller
> had timers). In fact, if we really need it, I'm sure we *could* find
> something somewhere in P8 that could act as a timer, probably hijacking
> a bit of the OCC or similar but at this stage, that's not on the radar.
>
> So make it an implementation statement. "However, not all
> implementations, such as some PowerPC ones, provide such an external
> timer ...".
Thanks for this information. I will update this going ahead.
Regards
Preeti U Murthy
next prev parent reply other threads:[~2013-12-13 5:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-13 4:19 [RFC PATCH] time: Support in tick broadcast framework for archs without an external wakeup source Preeti U Murthy
2013-12-13 5:17 ` Benjamin Herrenschmidt
2013-12-13 5:21 ` Preeti U Murthy [this message]
2013-12-16 4:36 ` Preeti U Murthy
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=52AA9953.9090909@linux.vnet.ibm.com \
--to=preeti@linux$(echo .)vnet.ibm.com \
--cc=arnd@arndb$(echo .)de \
--cc=benh@kernel$(echo .)crashing.org \
--cc=chenhui.zhao@freescale$(echo .)com \
--cc=deepthi@linux$(echo .)vnet.ibm.com \
--cc=fweisbec@gmail$(echo .)com \
--cc=geoff@infradead$(echo .)org \
--cc=john.stultz@linaro$(echo .)org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-pm@vger$(echo .)kernel.org \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=michael@ellerman$(echo .)id.au \
--cc=mingo@kernel$(echo .)org \
--cc=paul.gortmaker@windriver$(echo .)com \
--cc=paulmck@linux$(echo .)vnet.ibm.com \
--cc=paulus@samba$(echo .)org \
--cc=peterz@infradead$(echo .)org \
--cc=r58472@freescale$(echo .)com \
--cc=rafael.j.wysocki@intel$(echo .)com \
--cc=rostedt@goodmis$(echo .)org \
--cc=schwidefsky@de$(echo .)ibm.com \
--cc=shangw@linux$(echo .)vnet.ibm.com \
--cc=srivatsa.bhat@linux$(echo .)vnet.ibm.com \
--cc=tglx@linutronix$(echo .)de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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