On Fri, Jan 21, 2011 at 07:13:48PM +0530, Santosh Shilimkar wrote:
> > -----Original Message-----
> > From: Rob Herring [mailto:robherri...@gmail.com]
> > Sent: Thursday, January 20, 2011 10:05 PM
> > To: Santosh Shilimkar
> > Cc: linux-arm-ker...@lists.infradead.org; Russell King; linux-
> > o...@vger.kernel.org; Linus Walleij
> > Subject: Re: [PATCH] ARM: smp: Introduce ARCH_HAS_COMMON_CORES_CLOCK
> > to speed-up boot
>
> [..]
>
> > >>
> > >> There's already one way to do this with pre-calculated lpj.
> > >>
> > > How about the hot-plug path? This is not for just boot.
> >
> > The path is the same for hotplug and secondary boot, so yes for
> > both.
> > Plus you get the added benefit of speeding up the primary core boot
> > as well.
> >
> No 'preset_lpj' will not work for the hotplug path when
> cpufreq is active. It just useful only for boot in
> its current form.
Indeed, it will end up screwing up the loops_per_jiffy value. That
would seem to be a hole on other architectures too. I wonder if
anyone has tested hotplug on a cpufreq-scaled system.
> @@ -332,14 +345,19 @@ void __init smp_cpus_done(unsigned int max_cpus)
> int cpu;
> unsigned long bogosum = 0;
>
> - for_each_online_cpu(cpu)
> - bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
> + if (!skip_secondary_calibrate) {
> + for_each_online_cpu(cpu)
> + bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
>
> - printk(KERN_INFO "SMP: Total of %d processors activated "
> - "(%lu.%02lu BogoMIPS).\n",
> - num_online_cpus(),
> - bogosum / (500000/HZ),
> - (bogosum / (5000/HZ)) % 100);
> + printk(KERN_INFO "SMP: Total of %d processors activated "
> + "(%lu.%02lu BogoMIPS).\n",
> + num_online_cpus(),
> + bogosum / (500000/HZ),
> + (bogosum / (5000/HZ)) % 100);
> + } else {
> + printk(KERN_INFO "SMP: Total of %d processors
> activated.\n",
> + num_online_cpus());
> + }
Hmm. How about:
char bogosum[32];
if (!skip_secondary_calibrate) {
for_each_online_cpu(cpu)
bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
snprintf(bogosum, sizeof(bogosum), " (%lu.%02lu BogoMIPS).\n",
bogosum / (500000/HZ), (bogosum / (5000/HZ)) % 100);
} else
bogosum[0] = '\0';
pr_info("SMP: Total of %d processors activated%s.\n",
num_online_cpus(), bogosum);
Looks neater and more compact and reduces the amount of string space
required.
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
