From: "H. Peter Anvin" <hpa@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Feng Tang <feng.tang@intel.com>,
John Stultz <john.stultz@linaro.org>, Ingo Molnar <mingo@elte.hu>,
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 4/5] clocksource: Enable clocksource_cyc2ns() to cover big cycles
Date: Wed, 06 Mar 2013 13:05:26 -0800 [thread overview]
Message-ID: <5137AF96.6050003@linux.intel.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1303061451340.22263@ionos>
On 03/06/2013 06:09 AM, Thomas Gleixner wrote:
>
> This breaks everything which does not have a 64/32bit divide
> instruction. And you can't replace it with do_div() as that would
> impose massive overhead on those architectures in the fast path.
>
Could we do the same kind of scaling-by-multiplication that we do in
kernel/time.c for this?
-hpa
next prev parent reply other threads:[~2013-03-06 21:05 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 [this message]
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
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