From: Alex Shi <alex.shi@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Len Brown <len.brown@intel.com>
Cc: daniel.lezcano@linaro.org, linux-pm@vger.kernel.org
Subject: Re: [RFC PATCH] cpuidle: reduce unnecessary loop in c-state selection
Date: Wed, 22 Jan 2014 15:53:21 +0800 [thread overview]
Message-ID: <52DF78F1.7080204@linaro.org> (raw)
In-Reply-To: <13647359.XRIaiKjIK6@vostro.rjw.lan>
On 01/16/2014 11:53 PM, Rafael J. Wysocki wrote:
> Hi Len, what do you think?
Is this patch correct?
>
> On Thursday, January 16, 2014 08:45:16 PM Alex Shi wrote:
>> All deeper c-state have the longer target_residency and exit_latency
>> So, if the one can not meet our prediction, neither any later.
>> So, just break out the for loop to save few checking instructions.
>>
>> Signed-off-by: Alex Shi <alex.shi@linaro.org>
>> ---
>> drivers/cpuidle/governors/menu.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
>> index cf7f2f0..48ed3fb 100644
>> --- a/drivers/cpuidle/governors/menu.c
>> +++ b/drivers/cpuidle/governors/menu.c
>> @@ -352,11 +352,11 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
>> if (s->disabled || su->disable)
>> continue;
>> if (s->target_residency > data->predicted_us)
>> - continue;
>> + break;
>> if (s->exit_latency > latency_req)
>> - continue;
>> + break;
>> if (s->exit_latency * multiplier > data->predicted_us)
>> - continue;
>> + break;
>>
>> data->last_state_idx = i;
>> data->exit_us = s->exit_latency;
>>
>
--
Thanks
Alex
next prev parent reply other threads:[~2014-01-22 7:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-16 12:45 [RFC PATCH] cpuidle: reduce unnecessary loop in c-state selection Alex Shi
2014-01-16 15:53 ` Rafael J. Wysocki
2014-01-22 7:53 ` Alex Shi [this message]
2014-01-22 8:19 ` Daniel Lezcano
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