From: Huang Rui <ray.huang@amd.com>
To: Borislav Petkov <bp@suse.de>
Cc: "Guenter Roeck" <linux@roeck-us.net>,
"Peter Zijlstra" <peterz@infradead.org>,
"Jean Delvare" <jdelvare@suse.de>,
"Andy Lutomirski" <luto@amacapital.net>,
"Andreas Herrmann" <herrmann.der.user@gmail.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <lenb@kernel.org>,
"John Stultz" <john.stultz@linaro.org>,
"Frédéric Weisbecker" <fweisbec@gmail.com>,
lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org,
x86@kernel.org,
"Andreas Herrmann" <herrmann.der.user@googlemail.com>,
"Aravind Gopalakrishnan" <Aravind.Gopalakrishnan@amd.com>,
"Fengguang Wu" <fengguang.wu@intel.com>,
"Aaron Lu" <aaron.lu@intel.com>, "Tony Li" <tony.li@amd.com>
Subject: Re: [PATCH v2 05/10] hwmon: (fam15h_power) Add compute unit accumulated power
Date: Wed, 28 Oct 2015 13:06:36 +0800 [thread overview]
Message-ID: <20151028050636.GH8036@hr-amur2> (raw)
In-Reply-To: <20151028003418.GA7802@nazgul.tnic>
On Wed, Oct 28, 2015 at 01:34:18AM +0100, Borislav Petkov wrote:
> On Tue, Oct 27, 2015 at 10:53:40AM +0800, Huang Rui wrote:
> > Preemption must be disabled when calling smp_call_function_many,
> > get_cpu would did that. Will get_online_cpus have the same behavior
> > like that?
>
> Well, get_online_cpus() protects you against CPU hotplug operations in
> general. If you want to protect yourself against CPUs going away only,
> then I guess get_cpu()/put_cpu() is fine.
>
> But since we're going to work with the masks as below, prohibiting any
> changes to cpu_online_mask is probably the better/safe thing to do, i.e.
>
> get_online_cpus();
> preempt_disable();
>
> smp_call_function_many( ... );
>
> preempt_enable();
> put_online_cpus();
>
> > That means "the value(cu_acc_power) of the compute unit", which does
> > not represent the value of one CPU core.
>
> No, I mean this: "This behavior can decrease IPI numbers between the
> unit's."
>
> I'm wondering whether it is really needed at all ...
>
OK, The real words are "This behavior can decrease IPI numbers between
the cores." Actually, the meaning also can be reflected from the
codes. So I could remove this sentence.
> > OK, how about below codes:
> >
> > ---
> > for (i = 0; i <= cores_per_cu / BITS_PER_LONG; i++) {
> > offset = cores_per_cu % BITS_PER_LONG;
> > if (i == cores_per_cu / BITS_PER_LONG) {
> > cpumask_bits(src_mask)[i] = GENMASK(offset -1, 0);
> > break;
> > }
> > cpumask_bits(src_mask)[i] = GENMASK(BITS_PER_LONG - 1, 0);
> > }
> >
> > for (i = 0; i < cu_num; i++) {
> > cpumask_shift_left(dst, src_mask, cores_per_cu * i);
> > cpumask_and(res, dst, cpu_online_mask);
> > cpumask_set_cpu(cpumask_any(res), mask);
> > }
>
> I think you can make it even simpler:
>
> /* prepare CU temp mask */
> for (i = 0; i < cores_per_cu; i++)
> cpumask_set_cpu(i, tmp_mask);
>
> for (i = 0; i < cu_num; i++) {
> /* WARN_ON for empty CU masks */
> WARN_ON(!cpumask_and(res_mask, tmp_mask, cpu_online_mask));
> cpumask_set(cpumask_any(res_mask), call_mask);
> cpumask_shift_right(tmp_mask, tmp_mask, cores_per_cu);
> }
>
> smp_call_function_many(call_mask, .... );
>
> Something like that...
>
Looks better. :)
Thanks,
Rui
next prev parent reply other threads:[~2015-10-28 5:07 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-20 2:28 [PATCH v2 00/10] hwmon: (fam15h_power) Introduce an accumulated power reporting algorithm Huang Rui
2015-10-20 2:28 ` [PATCH v2 01/10] hwmon: (fam15h_power) Refactor attributes for dynamically added Huang Rui
2015-10-23 13:42 ` Guenter Roeck
2015-10-26 1:58 ` Huang Rui
2015-10-26 2:14 ` Guenter Roeck
2015-10-26 2:25 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 02/10] hwmon: (fam15h_power) Enable power1_input on AMD Carrizo Huang Rui
2015-10-23 13:45 ` Guenter Roeck
2015-10-26 2:19 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 03/10] hwmon: (fam15h_power) Add max compute unit accumulated power Huang Rui
2015-10-20 2:28 ` [PATCH v2 04/10] x86, amd: add accessor for number of cores per compute unit Huang Rui
2015-10-20 2:28 ` [PATCH v2 05/10] hwmon: (fam15h_power) Add compute unit accumulated power Huang Rui
2015-10-20 7:24 ` kbuild test robot
2015-10-21 1:42 ` Huang Rui
2015-10-21 2:15 ` Guenter Roeck
2015-10-21 2:40 ` Huang Rui
2015-10-21 2:49 ` Guenter Roeck
2015-10-21 3:04 ` Huang Rui
2015-10-21 6:05 ` Jean Delvare
2015-10-21 6:28 ` Huang Rui
2015-10-23 13:27 ` Borislav Petkov
2015-10-23 13:37 ` Guenter Roeck
2015-10-27 2:53 ` Huang Rui
2015-10-28 0:34 ` Borislav Petkov
2015-10-28 5:06 ` Huang Rui [this message]
2015-10-20 2:28 ` [PATCH v2 06/10] hwmon: (fam15h_power) Add ptsc counter value for " Huang Rui
2015-10-23 13:59 ` Guenter Roeck
2015-10-26 3:37 ` Huang Rui
2015-10-26 4:36 ` Borislav Petkov
2015-10-20 2:28 ` [PATCH v2 07/10] hwmon: (fam15h_power) Introduce a cpu accumulated power reporting algorithm Huang Rui
2015-10-23 13:28 ` Borislav Petkov
2015-10-26 3:46 ` Huang Rui
2015-10-26 4:41 ` Borislav Petkov
2015-10-23 14:20 ` Guenter Roeck
2015-10-27 3:36 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 08/10] hwmon: (fam15h_power) Add documentation for previous TDP reporting Huang Rui
2015-10-20 2:28 ` [PATCH v2 09/10] hwmon: (fam15h_power) Add documentation for accumulated power algorithm Huang Rui
2015-10-23 10:22 ` Borislav Petkov
2015-10-20 2:28 ` [PATCH v2 10/10] MAINTAINERS: change the maintainer of fam15h_power driver Huang Rui
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