From: Ingo Molnar <mingo@elte.hu>
To: Jack Steiner <steiner@sgi.com>
Cc: tglx@linutronix.de, davej@redhat.com, yinghan@google.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86: Reduce clock calibration time during slave cpu startup
Date: Fri, 5 Aug 2011 12:46:35 +0200 [thread overview]
Message-ID: <20110805104635.GB13055@elte.hu> (raw)
In-Reply-To: <20110801184542.GA3939@sgi.com>
* Jack Steiner <steiner@sgi.com> wrote:
> +/*
> + * Check if another cpu is in the same socket and has already been calibrated.
> + * If found, use the previous value. This assumes all cores in the same physical
> + * socket have the same core frequency.
> +
> +unsigned long __cpuinit calibrate_delay_is_known(void)
> +{
> + int i, cpu = smp_processor_id();
> +
> + if (!tsc_disabled && !cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC))
> + return 0;
> +
> + for_each_online_cpu(i)
> + if (cpu_data(i).phys_proc_id == cpu_data(cpu).phys_proc_id)
> + return cpu_data(i).loops_per_jiffy;
Hm, why do we have to make such an assumption? Cannot we query the
core frequency?
Thanks,
Ingo
next prev parent reply other threads:[~2011-08-05 10:47 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-27 13:57 [PATCH] x86: Reduce clock calibration time during slave cpu startup Jack Steiner
2011-07-27 14:05 ` Dave Jones
[not found] ` <20110727141527.GA8453@sgi.com>
[not found] ` <20110727155200.GA25381@redhat.com>
2011-08-01 18:45 ` [PATCH v2] " Jack Steiner
2011-08-05 10:46 ` Ingo Molnar [this message]
2011-08-05 13:13 ` Jack Steiner
2011-08-05 13:16 ` Jack Steiner
2011-08-05 21:38 ` Ingo Molnar
2011-08-07 0:36 ` Matthew Garrett
2011-08-08 20:44 ` Jack Steiner
2011-08-09 15:06 ` Ingo Molnar
2011-08-09 15:18 ` Matthew Garrett
2011-08-11 20:14 ` [PATCH v3] " Jack Steiner
2011-08-06 0:21 ` [PATCH v2] " Yinghai Lu
2011-08-06 6:58 ` Ingo Molnar
2011-08-06 10:51 ` Robin Holt
2011-08-06 14:39 ` Jack Steiner
2011-08-26 23:56 ` [PATCH] " Andrew Morton
2011-08-26 23:57 ` Andrew Morton
2011-08-29 15:04 ` Jack Steiner
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