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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>
2009-06-15[CPUFREQ] ondemand: Uncouple minimal sampling rate from HZ in NO_HZ caseThomas Renninger
With this patch you have following minimal sampling rate restrictions: Kernel restrictions: If CONFIG_NO_HZ is set, the limit is 10ms fixed. If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the limits depend on the CONFIG_HZ option: HZ=1000: min=20000us (20ms) HZ=250: min=80000us (80ms) HZ=100: min=200000us (200ms) HW restrictions: Do not sample/poll more often than HW latency * 100 exported by the low level cpufreq HW driver The higher value of above restrictions is the minimal sampling rate that can be set (and can be seen via ondemand/sampling_rate_min sysfs file) Default sampling rate still is HW latency * 1000, but this will now end up in lower values on latest (Intel and AMD) hardware as these can switch really fast and sampling rate mostly was limited to the 80ms or 200ms (depending on whether HZ=250 or HZ=1000 is used). Signed-off-by: Thomas Renninger <trenn@suse.de> Cc: Pallipadi Venkatesh <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2009-05-26[CPUFREQ] fix timer teardown in ondemand governorMathieu Desnoyers
* Rafael J. Wysocki (rjw@sisk.pl) wrote: > This message has been generated automatically as a part of a report > of regressions introduced between 2.6.28 and 2.6.29. > > The following bug entry is on the current list of known regressions > introduced between 2.6.28 and 2.6.29. Please verify if it still should > be listed and let me know (either way). > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13186 > Subject : cpufreq timer teardown problem > Submitter : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > Date : 2009-04-23 14:00 (24 days old) > References : http://marc.info/?l=linux-kernel&m=124049523515036&w=4 > Handled-By : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > Patch : http://patchwork.kernel.org/patch/19754/ > http://patchwork.kernel.org/patch/19753/ > (updated changelog) cpufreq fix timer teardown in ondemand governor The problem is that dbs_timer_exit() uses cancel_delayed_work() when it should use cancel_delayed_work_sync(). cancel_delayed_work() does not wait for the workqueue handler to exit. The ondemand governor does not seem to be affected because the "if (!dbs_info->enable)" check at the beginning of the workqueue handler returns immediately without rescheduling the work. The conservative governor in 2.6.30-rc has the same check as the ondemand governor, which makes things usually run smoothly. However, if the governor is quickly stopped and then started, this could lead to the following race : dbs_enable could be reenabled and multiple do_dbs_timer handlers would run. This is why a synchronized teardown is required. The following patch applies to, at least, 2.6.28.x, 2.6.29.1, 2.6.30-rc2. Depends on patch cpufreq: remove rwsem lock from CPUFREQ_GOV_STOP call Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: Andrew Morton <akpm@linux-foundation.org> CC: gregkh@suse.de CC: stable@kernel.org CC: cpufreq@vger.kernel.org CC: Ingo Molnar <mingo@elte.hu> CC: rjw@sisk.pl CC: Ben Slusky <sluskyb@paranoiacs.org> 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>
2009-02-24[CPUFREQ] checkpatch cleanups for ondemand governor.Dave Jones
Signed-off-by: Dave Jones <davej@redhat.com>
2009-02-05[CPUFREQ] Make ignore_nice_load setting of ondemand work as expected.Venkatesh Pallipadi
ondemand micro-accounting of idle time changes broke ignore_nice_load sysfs setting due to a thinko in the code. The bug entry: http://bugzilla.kernel.org/show_bug.cgi?id=12310 Reported-by: Jim Bray <jimsantelmo@gmail.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2009-01-06cpumask: convert struct cpufreq_policy to cpumask_var_tRusty Russell
Impact: use new cpumask API to reduce memory usage This is part of an effort to reduce structure sizes for machines configured with large NR_CPUS. cpumask_t gets replaced by cpumask_var_t, which is either struct cpumask[1] (small NR_CPUS) or struct cpumask * (large NR_CPUS). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Acked-by: Dave Jones <davej@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-09[CPUFREQ] Fix BUG: using smp_processor_id() in preemptible codeAndrea Righi
Use get_cpu()/put_cpu() in cpufreq_ondemand init routine, instead of smp_processor_id() to avoid the following BUG: [ 35.313118] BUG: using smp_processor_id() in preemptible [00000000] code=: modprobe/4952 [ 35.313132] caller is cpufreq_gov_dbs_init+0xa/0x8f [cpufreq_ondemand] [ 35.313140] Pid: 4952, comm: modprobe Not tainted 2.6.27-rc5-mm1 #23 [ 35.313145] Call Trace: [ 35.313158] [<ffffffff80361ff7>] debug_smp_processor_id+0xd7/0xe0 [ 35.313167] [<ffffffffa010800a>] cpufreq_gov_dbs_init+0xa/0x8f [cpufreq_ondemand] [ 35.313176] [<ffffffff8020903b>] _stext+0x3b/0x160 [ 35.313185] [<ffffffff804768c5>] __mutex_unlock_slowpath+0xe5/0x190 [ 35.313195] [<ffffffff8026236a>] trace_hardirqs_on_caller+0xca/0x140 [ 35.313205] [<ffffffff8026ef4c>] sys_init_module+0xdc/0x210 [ 35.313212] [<ffffffff8020b7cb>] system_call_fastpath+0x16/0x1b Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ] Don't export governors for default governorSven Wegener
We don't need to export the governors for use as the default governor, because the default governor will be built-in anyway and we can access the symbol directly. This also fixes the following sparse warnings: drivers/cpufreq/cpufreq_conservative.c:578:25: warning: symbol 'cpufreq_gov_conservative' was not declared. Should it be static? drivers/cpufreq/cpufreq_ondemand.c:582:25: warning: symbol 'cpufreq_gov_ondemand' was not declared. Should it be static? drivers/cpufreq/cpufreq_performance.c:39:25: warning: symbol 'cpufreq_gov_performance' was not declared. Should it be static? drivers/cpufreq/cpufreq_powersave.c:38:25: warning: symbol 'cpufreq_gov_powersave' was not declared. Should it be static? drivers/cpufreq/cpufreq_userspace.c:190:25: warning: symbol 'cpufreq_gov_userspace' was not declared. Should it be static? Signed-off-by: Sven Wegener <sven.wegener@stealer.net> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ][6/6] cpufreq: Add idle microaccounting in ondemand governorvenkatesh.pallipadi@intel.com
Use get_cpu_idle_time_us() to get micro-accounted idle information. This enables ondemand to get more accurate idle and busy timings than the jiffy based calculation. As a result, we can decrease the ondemand safety gaurd band from 80-10 to 95-3. Results in more aggressive power savings. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ][4/6] cpufreq_ondemand: Parameterize down differentialvenkatesh.pallipadi@intel.com
Use a parameter for down differential, instead of hardcoded 10%. Follow-on patch changes the down-differential dynamically, based on whether we are using idle micro-accounting or not. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ][3/6] cpufreq: get_cpu_idle_time() changes in ondemand for ↵venkatesh.pallipadi@intel.com
idle-microaccounting Preparatory changes for doing idle micro-accounting in ondemand governor. get_cpu_idle_time() gets extra parameter and returns idle time and also the wall time that corresponds to the idle time measurement. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ][2/6] cpufreq: Change load calculation in ondemand for software ↵venkatesh.pallipadi@intel.com
coordination Change the load calculation algorithm in ondemand to work well with software coordination of frequency across the dependent cpus. Multiply individual CPU utilization with the average freq of that logical CPU during the measurement interval (using getavg call). And find the max CPU utilization number in terms of CPU freq. That number is then used to get to the target freq for next sampling interval. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ][1/6] cpufreq: Add cpu number parameter to __cpufreq_driver_getavg()venkatesh.pallipadi@intel.com
Add a cpu parameter to __cpufreq_driver_getavg(). This is needed for software cpufreq coordination where policy->cpu may not be same as the CPU on which we want to getavg frequency. A follow-on patch will use this parameter to getavg freq from all cpus in policy->cpus. Change since last patch. Fix the offline/online and suspend/resume oops reported by Youquan Song <youquan.song@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09[CPUFREQ] add error handling for cpufreq_register_governor() errorAkinobu Mita
Add error handling for cpufreq_register_governor() error Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: cpufreq@lists.linux.org.uk Signed-off-by: Dave Jones <davej@redhat.com>
2008-05-23cpufreq: use performance variant for_each_cpu_mask_nrMike Travis
Change references from for_each_cpu_mask to for_each_cpu_mask_nr where appropriate Reviewed-by: Paul Jackson <pj@sgi.com> Reviewed-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-17cpufreq: Initialise default governor before useJohannes Weiner
When the cpufreq driver starts up at boot time, it calls into the default governor which might not be initialised yet. This hurts when the governor's worker function relies on memory that is not yet set up by its init function. This migrates all governors from module_init() to fs_initcall() when being the default, as was already done in cpufreq_performance when it was the only possible choice. The performance governor is always initialized early because it might be used as fallback even when not being the default. Fixes at least one actual oops where ondemand is the default governor and cpufreq_governor_dbs() uses the uninitialised kondemand_wq work-queue during boot-time. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-04[CPUFREQ] allow ondemand and conservative cpufreq governors to be used as ↵Thomas Renninger
default Depending on the transition latency of the HW for cpufreq switches, the ondemand or conservative governor cannot be used with certain cpufreq drivers. Still the ondemand should be the default governor on a wide range of systems. This patch allows this and lets the governor fallback to the performance governor at cpufreq driver load time, if the driver does not support fast enough frequency switching. Main benefit is that on e.g. installation or other systems without userspace support a working dynamic cpufreq support can be achieved on most systems by simply loading the cpufreq driver. This is especially essential for recent x86(_64) laptop hardware which may rely on working dynamic cpufreq OS support. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-06-21[CPUFREQ] ondemand: fix tickless accounting and software coordination bugVenki Pallipadi
With tickless kernel and software coordination os P-states, ondemand can look at wrong idle statistics. This can happen when ondemand sampling is happening on CPU 0 and due to software coordination sampling also looks at utilization of CPU 1. If CPU 1 is in tickless state at that moment, its idle statistics will not be uptodate and CPU 0 thinks CPU 1 is idle for less amount of time than it actually is. This can be resolved by looking at all the busy times of CPUs, which is accurate, even with tickless, and use that to determine idle time in a round about way (total time - busy time). Thanks to Arjan for originally reporting the ondemand bug on Lenovo T61. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2007-06-21[CPUFREQ] ondemand: add a check to avoid negative load calculationVenki Pallipadi
Due to rounding and inexact jiffy accounting, idle_ticks can sometimes be higher than total_ticks. Make sure those cases are handled as zero load case. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2007-05-08Add a new deferrable delayed work initVenki Pallipadi
Add a new deferrable delayed work init. This can be used to schedule work that are 'unimportant' when CPU is idle and can be called later, when CPU eventually comes out of idle. Use this init in cpufreq ondemand governor. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-20[CPUFREQ] cpufreq_ondemand.c: don't use _WORK_NAROleg Nesterov
Looks like dbs_timer() is very careful wrt per_cpu(cpu_dbs_info), and it doesn't need the help of WORK_STRUCT_NOAUTOREL. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: David Howells <dhowells@redhat.com> Signed-off-by: Dave Jones <davej@redhat.com>
2007-02-10[CPUFREQ] Whitespace fixupDave Jones
Signed-off-by: Dave Jones <davej@redhat.com>
2007-02-10[CPUFREQ] ondemand governor use new cpufreq rwsem locking in work callbackVenkatesh Pallipadi
Eliminate flush_workqueue in cpufreq_governor(STOP) callpath. Using flush there has a deadlock potential as in http://uwsg.iu.edu/hypermail/linux/kernel/0611.3/1223.html Also, cleanup the locking issues with do_dbs_timer delayed_work callback. As it changes the CPU frequency using __cpufreq_target, it needs to have policy_rwsem in write mode, which also protects it from hot plug. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-02-10[CPUFREQ] ondemand governor restructure the work callbackVenkatesh Pallipadi
Restructure the delayed_work callback in ondemand. This eliminates the need for smp_processor_id in the callback function and also helps in proper locking and avoiding flush_workqueue when stopping the governor (done in subsequent patch). Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-02-10[CPUFREQ] Remove hotplug cpu crapDave Jones
The hotplug CPU locking in cpufreq is horrendous. No-one seems to care enough to fix it, so just remove it so that the 99.9% of the real world users of this code can use cpufreq without being bothered by warnings. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2006-12-12Merge ../linusDave Jones
Conflicts: drivers/cpufreq/cpufreq.c
2006-11-22WorkStruct: make allyesconfigDavid Howells
Fix up for make allyesconfig. Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-06[CPUFREQ] Fix coding style issues in cpufreq.Gautham R Shenoy
Clean up cpufreq subsystem to fix coding style issues and to improve the readability. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-21[CPUFREQ] handle sysfs errorsJeff Garzik
Signed-off-by: Jeff Garzik <jeff@garzik.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-15[CPUFREQ][8/8] acpi-cpufreq: Add support for freq feedback from hardwareVenkatesh Pallipadi
Enable ondemand governor and acpi-cpufreq to use IA32_APERF and IA32_MPERF MSR to get active frequency feedback for the last sampling interval. This will make ondemand take right frequency decisions when hardware coordination of frequency is going on. Without APERF/MPERF, ondemand can take wrong decision at times due to underlying hardware coordination or TM2. Example: * CPU 0 and CPU 1 are hardware cooridnated. * CPU 1 running at highest frequency. * CPU 0 was running at highest freq. Now ondemand reduces it to some intermediate frequency based on utilization. * Due to underlying hardware coordination with other CPU 1, CPU 0 continues to run at highest frequency (as long as other CPU is at highest). * When ondemand samples CPU 0 again next time, without actual frequency feedback from APERF/MPERF, it will think that previous frequency change was successful and can go to wrong target frequency. This is because it thinks that utilization it has got this sampling interval is when running at intermediate frequency, rather than actual highest frequency. More information about IA32_APERF IA32_MPERF MSR: Refer to IA-32 Intel® Architecture Software Developer's Manual at http://developer.intel.com Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-09-05[CPUFREQ] Fix sparse warning in ondemandDave Jones
drivers/cpufreq/cpufreq_ondemand.c:323:2: warning: Using plain integer as NULL pointer Signed-off-by: Dave Jones <davej@redhat.com>
2006-08-14[CPUFREQ] make drivers/cpufreq/cpufreq_ondemand.c:powersave_bias_target() staticAdrian Bunk
This patch makes the needlessly global powersave_bias_target() static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Dave Jones <davej@redhat.com>
2006-08-11[CPUFREQ][2/2] ondemand: updated add powersave_bias tunableAlexey Starikovskiy
ondemand selects the minimum frequency that can retire a workload with negligible idle time -- ideally resulting in the highest performance/power efficiency with negligible performance impact. But on some systems and some workloads, this algorithm is more performance biased than necessary, and de-tuning it a bit to allow some performance impact can save measurable power. This patch adds a "powersave_bias" tunable to ondemand to allow it to reduce its target frequency by a specified percent. By default, the powersave_bias is 0 and has no effect. powersave_bias is in units of 0.1%, so it has an effective range of 1 through 1000, resulting in 0.1% to 100% impact. In practice, users will not be able to detect a difference between 0.1% increments, but 1.0% increments turned out to be too large. Also, the max value of 1000 (100%) would simply peg the system in its deepest power saving P-state, unless the processor really has a hardware P-state at 0Hz:-) For example, If ondemand requests 2.0GHz based on utilization, and powersave_bias=100, this code will knock 10% off the target and seek a target of 1.8GHz instead of 2.0GHz until the next sampling. If 1.8 is an exact match with an hardware frequency we use it, otherwise we average our time between the frequency next higher than 1.8 and next lower than 1.8. Note that a user or administrative program can change powersave_bias at run-time depending on how they expect the system to be used. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi at intel.com> Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy at intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-08-11[CPUFREQ][1/2] ondemand: updated tune for hardware coordinationAlexey Starikovskiy
Try to make dbs_check_cpu() call on all CPUs at the same jiffy. This will help when multiple cores share P-states via Hardware Coordination. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi at intel.com> Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy at intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-07-26[PATCH] Reorganize the cpufreq cpu hotplug locking to not be totally bizareArjan van de Ven
The patch below moves the cpu hotplugging higher up in the cpufreq layering; this is needed to avoid recursive taking of the cpu hotplug lock and to otherwise detangle the mess. The new rules are: 1. you must do lock_cpu_hotplug() around the following functions: __cpufreq_driver_target __cpufreq_governor (for CPUFREQ_GOV_LIMITS operation only) __cpufreq_set_policy 2. governer methods (.governer) must NOT take the lock_cpu_hotplug() lock in any way; they are called with the lock taken already 3. if your governer spawns a thread that does things, like calling __cpufreq_driver_target, your thread must honor rule #1. 4. the policy lock and other cpufreq internal locks nest within the lock_cpu_hotplug() lock. I'm not entirely happy about how the __cpufreq_governor rule ended up (conditional locking rule depending on the argument) but basically all callers pass this as a constant so it's not too horrible. The patch also removes the cpufreq_governor() function since during the locking audit it turned out to be entirely unused (so no need to fix it) The patch works on my testbox, but it could use more testing (otoh... it can't be much worse than the current code) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-23[cpufreq] ondemand: make shutdown sequence more robustLinus Torvalds
Shutting down the ondemand policy was fraught with potential problems, causing issues for SMP suspend (which wants to hot- unplug) all but the last CPU. This should fix at least the worst problems (divide-by-zero and infinite wait for the workqueue to shut down). Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-30[CPUFREQ] Misc cleanups in ondemand.Venkatesh Pallipadi
Misc cleanups in ondemand. Should have zero functional impact. Also adding Alexey as author. Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-06-30[CPUFREQ] Make ondemand sampling per CPU and remove the mutex usage in ↵Venkatesh Pallipadi
sampling path. Make ondemand sampling per CPU and remove the mutex usage in sampling path. Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-06-30[CPUFREQ] Remove slowdown from ondemand sampling path.Venkatesh Pallipadi
Remove slowdown from ondemand sampling path. This reduces the code path length in dbs_check_cpu() by half. slowdown was not used by ondemand by default. If there are any user level tools that were using this tunable, they may report error now. Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-06-23[PATCH] cpufreq build fixAndrew Morton
drivers/cpufreq/cpufreq_ondemand.c: In function 'do_dbs_timer': drivers/cpufreq/cpufreq_ondemand.c:374: warning: implicit declaration of function 'lock_cpu_hotplug' drivers/cpufreq/cpufreq_ondemand.c:381: warning: implicit declaration of function 'unlock_cpu_hotplug' drivers/cpufreq/cpufreq_conservative.c: In function 'do_dbs_timer': drivers/cpufreq/cpufreq_conservative.c:425: warning: implicit declaration of function 'lock_cpu_hotplug' drivers/cpufreq/cpufreq_conservative.c:432: warning: implicit declaration of function 'unlock_cpu_hotplug' Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-21[CPUFREQ] Fix ondemand vs suspend deadlockVenkatesh Pallipadi
Rootcaused the bug to a deadlock in cpufreq and ondemand. Due to non-existent ordering between cpu_hotplug lock and dbs_mutex. Basically a race condition between cpu_down() and do_dbs_timer(). cpu_down() flow: * cpu_down() call for CPU 1 * Takes hot plug lock * Calls pre down notifier * cpufreq notifier handler calls cpufreq_driver_target() which takes cpu_hotplug lock again. OK as cpu_hotplug lock is recursive in same process context * CPU 1 goes down * Calls post down notifier * cpufreq notifier handler calls ondemand event stop which takes dbs_mutex So, cpu_hotplug lock is taken before dbs_mutex in this flow. do_dbs_timer is triggerred by a periodic timer event. It first takes dbs_mutex and then takes cpu_hotplug lock in cpufreq_driver_target(). Note the reverse order here compared to above. So, if this timer event happens at right moment during cpu_down, system will deadlok. Attached patch fixes the issue for both ondemand and conservative. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-05-08[PATCH] x86_64: Move ondemand timer into own work queueAndi Kleen
Taking the cpu hotplug semaphore in a normal events workqueue is unsafe because other tasks can wait for any workqueues with it hold. This results in a deadlock. Move the DBS timer into its own work queue which is not affected by other work queue flushes to avoid this. Has been acked by Venkatesh. Cc: venkatesh.pallipadi@intel.com Cc: cpufreq@lists.linux.org.uk Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26[PATCH] cpufreq_ondemand: add range checkDominik Brodowski
Assert that cpufreq_target is, at least, called with the minimum frequency allowed by this policy, not something lower. It triggered problems on ARM. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2006-03-26[PATCH] cpufreq_ondemand: keep ignore_nice_load value when it is reselectedEric Piel
Keep the value of ignore_nice_load of the ondemand governor even after the governor has been deselected and selected back. This is the behavior of the other exported values of the ondemand governor and it's much more user-friendly. Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2006-03-26[PATCH] cpufreq_ondemand: Warn if it cannot run due to too long transition ↵Eric Piel
latency Display a warning if the ondemand governor can not be selected due to a transition latency of the cpufreq driver which is too long. Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2006-02-28[CPUFREQ] Lots of whitespace & CodingStyle cleanup.Dave Jones
Signed-off-by: Dave Jones <davej@redhat.com>
2006-01-18[CPUFREQ] Convert drivers/cpufreq semaphores to mutexes.akpm@osdl.org
Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Dave Jones <davej@redhat.com>
2005-12-01[PATCH] cpufreq_conservative/ondemand: invert meaning of 'ignore nice'Alexander Clouter
The use of the 'ignore_nice' sysfs file is confusing to anyone using it. This removes the sysfs file 'ignore_nice' and in its place creates a 'ignore_nice_load' entry that defaults to '0'; meaning nice'd processes _are_ counted towards the 'business' calculation. WARNING: this obvious breaks any userland tools that expected ignore_nice' to exist, to draw attention to this fact it was concluded on the mailing list that the entry should be removed altogether so the userland app breaks and so the author can build simple to detect workaround. Having said that it seems currently very few tools even make use of this functionality; all I could find was a Gentoo Wiki entry. 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>