linux-kernel - Re: [PATCH v6] clocksource:arm_global_timer: Add ARM global timer support.

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]

Date:	Tue, 25 Jun 2013 16:00:25 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Srinivas KANDAGATLA <srinivas.kandagatla@...com>
cc:	John Stultz <john.stultz@...aro.org>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <rob.herring@...xeda.com>,
	Rob Landley <rob@...dley.net>,
	devicetree-discuss@...ts.ozlabs.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Linus Walleij <linus.walleij@...aro.org>,
	Stuart Menefy <stuart.menefy@...com>,
	Arnd Bergmann <arnd@...db.de>,
	Rob Herring <robherring2@...il.com>,
	Will Deacon <will.deacon@....com>
Subject: Re: [PATCH v6] clocksource:arm_global_timer: Add ARM global timer
 support.

On Tue, 25 Jun 2013, Srinivas KANDAGATLA wrote:
> On 25/06/13 14:17, Thomas Gleixner wrote:
> > On Tue, 25 Jun 2013, Srinivas KANDAGATLA wrote:
> >> +static void gt_compare_set(unsigned long delta, int periodic)
> >> +{
> >> +	u64 counter = gt_counter_read();
> >> +	unsigned long ctrl = readl(gt_base + GT_CONTROL);
> > 
> > Why are you reading the control register back over and over? All you
> > need to preserve is the GT_CONTROL_TIMER_ENABLE bit. So you can spare
> > that read out and just do
> > 
> > 	ctrl = GT_CONTROL_TIMER_ENABLE;
> > 	writel(ctrl, gt_base + GT_CONTROL);
> 
> Logically you are right we could do as you suggested, However its not
> implicit that which bits are going to be cleared. Its more to do with
> readability of the code.
> If you still insist I can change it.

I'm not insisting. I just pointed out, that you can save cycles in a
hotpath. :)

Thanks,

	tglx
--
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/