From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Balbir Singh <bsingharora@gmail.com>,
Shreyas B Prabhu <shreyas@linux.vnet.ibm.com>,
rjw@rjwysocki.net
Cc: linux-pm@vger.kernel.org, anton@samba.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] cpuidle/powernv: Fix snooze timeout
Date: Thu, 23 Jun 2016 12:01:57 +0200 [thread overview]
Message-ID: <576BB395.5050502@linaro.org> (raw)
In-Reply-To: <576BABC5.7020600@gmail.com>
On 06/23/2016 11:28 AM, Balbir Singh wrote:
[ ... ]
>> cpuidle_enter_state()
>> {
>> [...]
>> time_start = local_clock();
>> [enter idle state]
>> time_end = local_clock();
>> /*
>> * local_clock() returns the time in nanosecond, let's shift
>> * by 10 (divide by 1024) to have microsecond based time.
>> */
>> diff = (time_end - time_start) >> 10;
>> [...]
>> dev->last_residency = (int) diff;
>> }
>>
>> Because of >>10 as opposed to /1000, last_residency is lesser by 2.3%
I am surprised the last_residency is 2.3% exactly less. The difference
between >>10 and /1000 is 2.34%.
What is the next target residency value ?
Does it solve the issue if you replace >>10 by /1000 ?
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next prev parent reply other threads:[~2016-06-23 10:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 19:36 [PATCH] cpuidle/powernv: Fix snooze timeout Shreyas B. Prabhu
2016-06-22 22:49 ` Rafael J. Wysocki
2016-06-22 23:48 ` Balbir Singh
2016-06-23 4:58 ` Shreyas B Prabhu
2016-06-23 9:28 ` Balbir Singh
2016-06-23 9:41 ` Shreyas B Prabhu
2016-06-23 9:55 ` Balbir Singh
2016-06-23 10:01 ` Daniel Lezcano [this message]
2016-06-23 13:35 ` Shreyas B Prabhu
2016-06-23 14:36 ` Daniel Lezcano
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