linux-kernel - Re: [PATCH] clocksource: dw_apb_timer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6198599.NHtefZl19R@wuerfel>
Date:	Tue, 03 Nov 2015 09:49:32 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	Jisheng Zhang <jszhang@...vell.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>, tglx@...utronix.de,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clocksource: dw_apb_timer_of: support timer-based delay

On Tuesday 03 November 2015 14:59:40 Jisheng Zhang wrote:
> > On Monday 02 November 2015 11:03:34 Jisheng Zhang wrote:
> > > On Fri, 30 Oct 2015 13:42:01 +0100 Arnd Bergmann wrote:  
> > I'd be happier with a solution that keeps the DT describing the hardware
> > and not the way we expect Linux to use it, and instead has some heuristic
> > in the selection of the delay timer. At the moment, we purely base this
> > on the frequency, which as you say is suboptimal.
> > 
> > One possible way to improve this would be to add an optional 'latency'
> > property to the DT nodes (or the driver), and use a combination of latency
> > and resolution to make the decision.
> 
> Got it. Thanks for the suggestions. The 'latency' here seems a 'rating'
> similar as the one in clocksource. I will cook a series for review:
> 
> patch 1 to make register_current_timer_delay() aware of 'rating'
> 
> patch 2 to set rating of arch timer as 400
> 
> patch 3 to add timer based delay support to dw_apb_timer whose rating is 300

Ok. Just to make sure I got this right: your plan is to use the existing
'rating' setting as a primary indication, and fall back to comparing the
frequency if the rating is the same?

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/