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Commit d838cb3b authored by Saravana Kannan's avatar Saravana Kannan
Browse files

devfreq: governor_cpubw_hwmon: Remove sample_ms and fix round up of freq 



devfreq already provides a sysfs interface for changing polling/sampling
period. So, there is no need for the governor to separately expose
sampling_ms. Also, sampling_ms had to be explicitly updated whenever
polling_ms was updated for the governor to function correctly. Make the
interface simpler by combining sample_ms with polling_interval control
provided by devfreq.

The rounding of freq to multiples of bw_step is unnecessary since the
devfreq device already does the rounding to the next valid level. Rounding
of AB to multiples of bw_step is still necessary since it's a vote that's
summed up and doesn't have a direct 1-to-1 mapping to frequencies.

Also update default bw_step to 190 MB/s instead of 200 MB/s to account for
the fact that MB/s to MHz conversion needs to take into account the
difference in the meaning of M (2^20 vs 10^6) between MB and MHz. Similarly
also update io_percent to 16.

Change-Id: I5fea989c647955103de3813be8eb9ec612f131bc
Signed-off-by: default avatarSaravana Kannan <skannan@codeaurora.org>
parent 5f4d31f2

drivers/devfreq/governor_cpubw_hwmon.c

+17 −8
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2013, The Linux Foundation. All rights reserved.

 * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and
@@ -77,13 +77,15 @@ static DEVICE_ATTR(__attr, 0644, show_##__attr, store_##__attr) 


static int l2pm_irq;

static unsigned int bytes_per_beat;

static unsigned int sample_ms = 50;

static unsigned int tolerance_percent = 10;

static unsigned int guard_band_mbps = 100;

static unsigned int decay_rate = 90;

static unsigned int io_percent = 15;

static unsigned int bw_step = 200;

static unsigned int io_percent = 16;

static unsigned int bw_step = 190;



#define MIN_MS	10U

#define MAX_MS	500U

static unsigned int sample_ms = 50;

static u32 prev_r_start_val;

static u32 prev_w_start_val;

static unsigned long prev_ab;
@@ -245,7 +247,7 @@ static void compute_bw(int mbps, unsigned long *freq, unsigned long *ab) 
	}



	*ab = roundup(mbps, bw_step);

	*freq = roundup((mbps * 100) / io_percent, bw_step);

	*freq = (mbps * 100) / io_percent;

}



#define TOO_SOON_US	(1 * USEC_PER_MSEC)
@@ -343,7 +345,6 @@ static int devfreq_cpubw_hwmon_get_freq(struct devfreq *df, 
	return 0;

}



gov_attr(sample_ms, 10U, 500U);

gov_attr(tolerance_percent, 0U, 30U);

gov_attr(guard_band_mbps, 0U, 2000U);

gov_attr(decay_rate, 0U, 100U);
@@ -351,7 +352,6 @@ gov_attr(io_percent, 1U, 100U); 
gov_attr(bw_step, 50U, 1000U);



static struct attribute *dev_attr[] = {

	&dev_attr_sample_ms.attr,

	&dev_attr_tolerance_percent.attr,

	&dev_attr_guard_band_mbps.attr,

	&dev_attr_decay_rate.attr,
@@ -378,7 +378,13 @@ static int devfreq_cpubw_hwmon_ev_handler(struct devfreq *df, 
		ret = sysfs_create_group(&df->dev.kobj, &dev_attr_group);

		if (ret)

			return ret;



		sample_ms = df->profile->polling_ms;

		sample_ms = max(MIN_MS, sample_ms);

		sample_ms = min(MAX_MS, sample_ms);

		df->profile->polling_ms = sample_ms;

		devfreq_monitor_start(df);



		pr_debug("Enabled CPU BW HW monitor governor\n");

		break;
@@ -391,7 +397,10 @@ static int devfreq_cpubw_hwmon_ev_handler(struct devfreq *df, 
		break;



	case DEVFREQ_GOV_INTERVAL:

		devfreq_interval_update(df, (unsigned int *)data);

		sample_ms = *(unsigned int *)data;

		sample_ms = max(MIN_MS, sample_ms);

		sample_ms = min(MAX_MS, sample_ms);

		devfreq_interval_update(df, &sample_ms);

		break;

	}