From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Timur Tabi <timur@freescale.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Grant Likely <grant.likely@secretlab.ca>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org, rdreier@cisco.com,
jirislaby@gmail.com, will.newton@gmail.com, hancockrwd@gmail.com,
jeremy@goop.org
Subject: Re: [PATCH v4] introduce macro spin_event_timeout()
Date: Fri, 13 Mar 2009 14:03:41 +1100 [thread overview]
Message-ID: <1236913421.25062.19.camel@pasglop> (raw)
In-Reply-To: <ed82fe3e0903121205k552a83bft9ac3b63c64a293c8@mail.gmail.com>
> But that's the thing - I don't want a required delay inside the loop.
>
> I guess I'm going to have to think about this for a while. I'd like
> to see something like cycles_per_usec() as a companion function to
> get_cycles().
I think that's where you're wrong :-)
Just require the delay inside the loop, it will make everything nicer.
There are also some good reasons to do that:
- The delay between "polls" of the register may have to be controlled,
for example some HW will choke if polled too fast
- If you aren't in an atomic section, you may want to use msleep() and
thus be schedule friendly
- It fixes all the problems mentioned earlier
Cheers,
Ben.
next prev parent reply other threads:[~2009-03-13 3:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-10 15:30 [PATCH v4] introduce macro spin_event_timeout() Timur Tabi
2009-03-10 15:35 ` Alan Cox
2009-03-10 15:50 ` Timur Tabi
2009-03-10 16:05 ` Will Newton
2009-03-10 16:11 ` Timur Tabi
2009-03-11 0:01 ` Benjamin Herrenschmidt
2009-03-11 0:37 ` Alan Cox
2009-03-11 16:48 ` Timur Tabi
2009-03-11 16:58 ` Alan Cox
2009-03-11 18:18 ` Timur Tabi
2009-03-11 21:58 ` Benjamin Herrenschmidt
2009-03-12 2:45 ` Grant Likely
2009-03-12 15:54 ` Timur Tabi
2009-03-12 16:01 ` Grant Likely
2009-03-12 16:19 ` Timur Tabi
2009-03-12 16:50 ` Peter Zijlstra
2009-03-12 19:05 ` Timur Tabi
2009-03-13 3:03 ` Benjamin Herrenschmidt [this message]
2009-03-13 4:51 ` Grant Likely
2009-03-10 18:41 ` Grant Likely
2009-03-10 19:04 ` Timur Tabi
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