From: Thomas Gleixner <tglx@linutronix.de>
To: Feng Tang <feng.tang@intel.com>
Cc: John Stultz <john.stultz@linaro.org>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
x86@kernel.org, Len Brown <lenb@kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
linux-kernel@vger.kernel.org, gong.chen@linux.intel.com
Subject: Re: [PATCH v3 5/5] timekeeping: utilize the suspend-nonstop clocksource to count suspended time
Date: Wed, 6 Mar 2013 22:33:08 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.02.1303062231000.22263@ionos> (raw)
In-Reply-To: <20130306142914.GA25790@feng-snb>
On Wed, 6 Mar 2013, Feng Tang wrote:
> On Wed, Mar 06, 2013 at 03:15:49PM +0100, Thomas Gleixner wrote:
> > If the suspend time measured by the nonstop clocksource is 0.999 sec
> > then we throw it away and then let the RTC code inject inaccurate
> > sleep time? Brilliant design, really.
>
> Emm, I wrote the code with an assumption that the sleep itself and the
> enter/exit processes will be longer than 1 second.
>
> I can initialize the ts_delta to (0, 0} and change the check condition
> to
> if (ts_delta.tv_sec || ts_delta.tv_nsec)
>
To be honest, I hate this abuse of ts_delta as a condition. Use a
separate condition variable to make clear what the hell that code is
doing. This is not a fast path and I really prefer understandable code
over magic microoptimizations for no value.
Thanks,
tglx
prev parent reply other threads:[~2013-03-06 21:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 7:17 [PATCH v3 0/5] Add support for S3 non-stop TSC support Feng Tang
2013-03-06 7:17 ` [PATCH v3 1/5] x86: Add cpu capability flag X86_FEATURE_NONSTOP_TSC_S3 Feng Tang
2013-03-06 7:17 ` [PATCH v3 2/5] clocksource: Add new feature flag CLOCK_SOURCE_SUSPEND_NONSTOP Feng Tang
2013-03-06 7:17 ` [PATCH v3 3/5] x86: tsc: Add support for new S3_NONSTOP feature Feng Tang
2013-03-06 7:17 ` [PATCH v3 4/5] clocksource: Enable clocksource_cyc2ns() to cover big cycles Feng Tang
2013-03-06 14:09 ` Thomas Gleixner
2013-03-06 14:37 ` Feng Tang
2013-03-06 16:10 ` Thomas Gleixner
2013-03-06 16:26 ` Feng Tang
2013-03-06 21:05 ` H. Peter Anvin
2013-03-06 21:15 ` Thomas Gleixner
2013-03-06 21:20 ` H. Peter Anvin
2013-03-06 21:29 ` Thomas Gleixner
2013-03-06 7:17 ` [PATCH v3 5/5] timekeeping: utilize the suspend-nonstop clocksource to count suspended time Feng Tang
2013-03-06 14:15 ` Thomas Gleixner
2013-03-06 14:29 ` Feng Tang
2013-03-06 21:33 ` Thomas Gleixner [this message]
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