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2018-01-18powerpc/pseries/cpuidle: add polling idle for shared processor guestsNicholas Piggin1-2/+8
For shared processor guests (e.g., KVM), add an idle polling mode rather than immediately returning to the hypervisor when the guest CPU goes idle. Test setup is a 2 socket POWER9 with 4 guests running, each with vCPUs equal to 1/2 of real of CPUs. Saturated each guest with tbench. Using polling idle gives about 1.4x throughput. Kernel compile speed was not changed significantly. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-18cpuidle/powernv: avoid double irq enable coming out of idleNicholas Piggin1-2/+4
Since e1689795a7 ("cpuidle: Add common time keeping and irq enabling"), cpuidle drivers are expected to return from ->enter with irqs disabled. Update the cpuidle-powernv snooze and cede loops to disable irqs before returning. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-28cpuidle: powerpc: no memory barrier after break from idleNicholas Piggin1-2/+9
A memory barrier is not required after the task wakes up, only if we clear the polling flag before waking. The case where we have work to do is the important one, so optimise for it. Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-28cpuidle: powerpc: read mostly for common globalsNicholas Piggin1-4/+4
Ensure these don't get put into bouncing cachelines. Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-28cpuidle: powerpc: cpuidle set polling before enabling irqsNicholas Piggin1-1/+2
local_irq_enable can cause interrupts to be taken which could take significant amount of processing time. The idle process should set its polling flag before this, so another process that wakes it during this time will not have to send an IPI. Expand the TIF_POLLING_NRFLAG coverage to as large as possible. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-06cpuidle/pseries: Convert to hotplug state machineSebastian Andrzej Siewior1-27/+24
Install the callbacks via the state machine. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160818125731.27256-11-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-22cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle stateShilpasri G Bhat1-0/+11
The idle cpus which stay in snooze for a long period can degrade the perfomance of the sibling cpus. If the cpu stays in snooze for more than target residency of the next available idle state, then exit from snooze. This gives a chance to the cpuidle governor to re-evaluate the last idle state of the cpu to promote it to deeper idle states. Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-11-12cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logicDaniel Lezcano1-3/+0
The only place where the time is invalid is when the ACPI_CSTATE_FFH entry method is not set. Otherwise for all the drivers, the time can be correctly measured. Instead of duplicating the CPUIDLE_FLAG_TIME_VALID flag in all the drivers for all the states, just invert the logic by replacing it by the flag CPUIDLE_FLAG_TIME_INVALID, hence we can set this flag only for the acpi idle driver, remove the former flag from all the drivers and invert the logic with this flag in the different governor. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-12cpuidle/pseries: Fix fallout caused due to cleanup in pseries cpuidle ↵Preeti U Murthy1-0/+1
backend driver Commit d8c6ad3184ca651 ("sched/idle, PPC: Remove redundant cpuidle_idle_call()") reintroduced ppc64_runlatch_off/on() in the pseries cpuidle backend driver. Hence the cleanup caused by the commit "c0c4301c54adde05:pseries/cpuidle: Remove redundant call to ppc64_runlatch_off() in cpu idle routines" in conjuction with the commit d8c6ad3184ca651 causes a build failure. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/52FAFD2D.2090306@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-02-11sched/idle, PPC: Remove redundant cpuidle_idle_call()Nicolas Pitre1-0/+5
The core idle loop now takes care of it. However a few things need checking: - Invocation of cpuidle_idle_call() in pseries_lpar_idle() happened through arch_cpu_idle() and was therefore always preceded by a call to ppc64_runlatch_off(). To preserve this property now that cpuidle_idle_call() is invoked directly from core code, a call to ppc64_runlatch_off() has been added to idle_loop_prolog() in platforms/pseries/processor_idle.c. - Similarly, cpuidle_idle_call() was followed by ppc64_runlatch_off() so a call to the later has been added to idle_loop_epilog(). - And since arch_cpu_idle() always made sure to re-enable IRQs if they were not enabled, this is now done in idle_loop_epilog() as well. The above was made in order to keep the execution flow close to the original. I don't know if that was strictly necessary. Someone well aquainted with the platform details might find some room for possible optimizations. Signed-off-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-sh@vger.kernel.org Cc: linux-pm@vger.kernel.org Cc: Russell King <linux@arm.linux.org.uk> Cc: linaro-kernel@lists.linaro.org Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-47o4m03citrfg9y1vxic5asb@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-29powerpc/pseries/cpuidle: smt-snooze-delay cleanup.Deepthi Dharwar1-17/+0
smt-snooze-delay was designed to disable NAP state or delay the entry to the NAP state prior to adoption of cpuidle framework. This is per-cpu variable. With the coming of CPUIDLE framework, states can be disabled on per-cpu basis using the cpuidle/enable sysfs entry. Also, with the coming of cpuidle driver each state's target residency is per-driver unlike earlier which was per-device. Therefore, the per-cpu sysfs smt-snooze-delay which decides the target residency of the idle state on a particular cpu causes more confusion to the user as we cannot have different smt-snooze-delay (target residency) values for each cpu. In the current code, smt-snooze-delay functionality is completely broken. It makes sense to remove smt-snooze-delay from idle driver with the coming of cpuidle framework. However, sysfs files are retained as ppc64_util currently utilises it. Once we fix ppc64_util, propose to clean up the kernel code. Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-29powerpc/pseries/cpuidle: Remove MAX_IDLE_STATE macro.Deepthi Dharwar1-18/+10
This patch removes the usage of MAX_IDLE_STATE macro and dead code around it. The number of states are determined at run time based on the cpuidle state table selected on a given platform Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-29powerpc/pseries/cpuidle: Make cpuidle-pseries backend driver a non-module.Deepthi Dharwar1-14/+1
Currently cpuidle-pseries backend driver cannot be built as a module due to dependencies wrt cpuidle framework. This patch removes all the module related code in the driver. Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-29powerpc/pseries/cpuidle: Use cpuidle_register() for initialisation.Deepthi Dharwar1-67/+11
This patch replaces the cpuidle driver and devices initialisation calls with a single generic cpuidle_register() call and also includes minor refactoring of the code around it. Remove the cpu online check in snooze loop, as this code can only locally run on a cpu only if it is online. Therefore, this check is not required. Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-29powerpc/pseries/cpuidle: Move processor_idle.c to drivers/cpuidle.Deepthi Dharwar1-0/+361
Move the file from arch specific pseries/processor_idle.c to drivers/cpuidle/cpuidle-pseries.c Make the relevant Makefile and Kconfig changes. Also, introduce Kconfig.powerpc in drivers/cpuidle for all powerpc cpuidle drivers. Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>