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path: root/Documentation/cpu-freq/governors.txt
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2011-11-30Documentation: cpufreq: add description of timer_rateAllen Martin
Add description of timer_rate tunable and clean up some typos. Change-Id: I4b96a36aad51eed3bef0ee5f571dc6e0a94c8dd9 Signed-off-by: Allen Martin <amartin@nvidia.com>
2011-11-30Documentation: remove trailing whitespace in governors.txtAllen Martin
Fixes a checkpatch warning Change-Id: I2962b7c32f336188de0d2fe4f0f13f1199cb68e2 Signed-off-by: Allen Martin <amartin@nvidia.com>
2011-11-30cpufreq: interactive: New 'interactive' governorMike Chan
This governor is designed for latency-sensitive workloads, such as interactive user interfaces. The interactive governor aims to be significantly more responsive to ramp CPU quickly up when CPU-intensive activity begins. Existing governors sample CPU load at a particular rate, typically every X ms. This can lead to under-powering UI threads for the period of time during which the user begins interacting with a previously-idle system until the next sample period happens. The 'interactive' governor uses a different approach. Instead of sampling the CPU at a specified rate, the governor will check whether to scale the CPU frequency up soon after coming out of idle. When the CPU comes out of idle, a timer is configured to fire within 1-2 ticks. If the CPU is very busy from exiting idle to when the timer fires then we assume the CPU is underpowered and ramp to MAX speed. If the CPU was not sufficiently busy to immediately ramp to MAX speed, then the governor evaluates the CPU load since the last speed adjustment, choosing the highest value between that longer-term load or the short-term load since idle exit to determine the CPU speed to ramp to. A realtime thread is used for scaling up, giving the remaining tasks the CPU performance benefit, unlike existing governors which are more likely to schedule rampup work to occur after your performance starved tasks have completed. The tuneables for this governor are: /sys/devices/system/cpu/cpufreq/interactive/min_sample_time: The minimum amount of time to spend at the current frequency before ramping down. This is to ensure that the governor has seen enough historic CPU load data to determine the appropriate workload. Default is 80000 uS. /sys/devices/system/cpu/cpufreq/interactive/go_maxspeed_load The CPU load at which to ramp to max speed. Default is 85. Change-Id: Ib2b362607c62f7c56d35f44a9ef3280f98c17585 Signed-off-by: Mike Chan <mike@android.com> Signed-off-by: Todd Poynor <toddpoynor@google.com> Bug: 3152864
2011-03-16[CPUFREQ] Add documentation for sampling_down_factorVishwanath BS
Update cpufreq governor documentation for sampling_down_factor tunable parameter. Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com> Signed-off-by: Dave Jones <davej@redhat.com>
2010-01-13[CPUFREQ] fix default value for ondemand governorMike Frysinger
Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Dave Jones <davej@redhat.com>
2009-06-15[CPUFREQ] Only set sampling_rate_max deprecated, sampling_rate_min is usefulThomas Renninger
Update the documentation accordingly. Cleanup and use printk_once. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
2009-02-24[CPUFREQ] ondemand/conservative: sanitize sampling_rate restrictionsThomas Renninger
Limit sampling rate to transition_latency * 100 or kernel limits. If sampling_rate is tried to be set too low, set the lowest allowed value. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
2009-02-24[CPUFREQ] ondemand/conservative: deprecate sampling_rate{min,max}Thomas Renninger
The same info can be obtained via the transition_latency sysfs file Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
2008-07-26Documentation cleanup: trivial misspelling, punctuation, and grammar ↵Matt LaPlante
corrections. Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-20[CPUFREQ] Remove documentation of removed ondemand tunable.Dave Jones
sampling_down_factor was removed in ccb2fe209dac9ff67f6351e783e610073afaaeaf back in June 2006. Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-03Fix typos in Documentation/: 'N'-'P'Matt LaPlante
This patch fixes typos in various Documentation txts. The patch addresses some words starting with the letters 'N'-'P'. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-03Fix typos in Documentation/: 'H'-'M'Matt LaPlante
This patch fixes typos in various Documentation txts. The patch addresses some words starting with the letters 'H'-'M'. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-03Fix typos in Documentation/: 'F'-'G'Matt LaPlante
This patch fixes typos in various Documentation txts. The patch addresses some words starting with the letters 'F'-'G'. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2005-12-01[PATCH] cpufreq: documentation for 'ondemand' and 'conservative'Alexander Clouter
Added a more verbose entry for the 'ondemend' governor and an entry for the 'conservative' governor to the documentation. Signed-off-by: Alexander Clouter <alex-kernel@digriz.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Dave Jones <davej@redhat.com>
2005-06-25[PATCH] cpufreq: governors documentation fixesNico Golde
I corrected a small error and enhanced the govenor.txt file with the ondemand daemon because the kernel configs link to the documentation but ondemand wasn't documentated. Feel free to include the patch in the attachment. Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!