linux/kernel
Rik van Riel 5743021831 sched/cputime: Count actually elapsed irq & softirq time
Currently, if there was any irq or softirq time during 'ticks'
jiffies, the entire period will be accounted as irq or softirq
time.

This is inaccurate if only a subset of the time was actually spent
handling irqs, and could conceivably mis-count all of the ticks during
a period as irq time, when there was some irq and some softirq time.

This can actually happen when irqtime_account_process_tick is called
from account_idle_ticks, which can pass a larger number of ticks down
all at once.

Fix this by changing irqtime_account_hi_update(), irqtime_account_si_update(),
and steal_account_process_ticks() to work with cputime_t time units, and
return the amount of time spent in each mode.

Rename steal_account_process_ticks() to steal_account_process_time(), to
reflect that time is now accounted in cputime_t, instead of ticks.

Additionally, have irqtime_account_process_tick() take into account how
much time was spent in each of steal, irq, and softirq time.

The latter could help improve the accuracy of cputime
accounting when returning from idle on a NO_HZ_IDLE CPU.

Properly accounting how much time was spent in hardirq and
softirq time will also allow the NO_HZ_FULL code to re-use
these same functions for hardirq and softirq accounting.

Signed-off-by: Rik van Riel <riel@redhat.com>
[ Make nsecs_to_cputime64() actually return cputime64_t. ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1468421405-20056-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-14 10:42:34 +02:00
..
bpf bpf: fix matching of data/data_end in verifier 2016-06-15 23:37:54 -07:00
configs
debug mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings 2016-02-22 08:51:37 +01:00
events perf/core: Fix pmu::filter_match for SW-led groups 2016-07-07 08:57:57 +02:00
gcov gcov: disable for COMPILE_TEST 2016-05-10 17:12:49 +02:00
irq irqchip updates for 4.7-rc1: 2016-06-03 15:05:51 +02:00
livepatch Merge branches 'for-4.7/core', 'for-4.7/livepatching-doc' and 'for-4.7/livepatching-ppc64' into for-linus 2016-05-17 12:06:35 +02:00
locking locking: avoid passing around 'thread_info' in mutex debugging code 2016-06-23 12:11:17 -07:00
power oom, suspend: fix oom_reaper vs. oom_killer_disable race 2016-06-24 17:23:52 -07:00
printk printk/nmi: flush NMI messages on the system panic 2016-05-20 17:58:30 -07:00
rcu debugobjects: insulate non-fixup logic related to static obj from fixup callbacks 2016-05-19 19:12:14 -07:00
sched sched/cputime: Count actually elapsed irq & softirq time 2016-07-14 10:42:34 +02:00
time timer: Export destroy_hrtimer_on_stack() 2016-05-31 11:44:08 -07:00
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-06-29 11:50:42 -07:00
.gitignore certs: add .gitignore to stop git nagging about x509_certificate_list 2015-10-21 15:18:35 +01:00
acct.c
async.c async: export current_is_async() 2015-11-19 17:51:48 +01:00
audit.c Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit 2016-06-29 15:18:47 -07:00
audit.h audit: move audit_get_tty to reduce scope and kabi changes 2016-06-28 15:48:48 -04:00
audit_fsnotify.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
audit_tree.c audit: cleanup prune_tree_thread 2016-04-04 09:46:47 -04:00
audit_watch.c don't bother with ->d_inode->i_sb - it's always equal to ->d_sb 2016-04-10 17:11:51 -04:00
auditfilter.c audit: Fix typo in comment 2016-02-08 11:25:39 -05:00
auditsc.c Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit 2016-06-29 15:18:47 -07:00
backtracetest.c
bounds.c
capability.c
cgroup.c cgroup: Disable IRQs while holding css_set_lock 2016-06-23 17:23:12 -04:00
cgroup_freezer.c cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends 2015-12-03 10:24:08 -05:00
cgroup_pids.c cgroup_pids: fix a typo. 2015-12-14 14:54:37 -05:00
compat.c
configs.c
context_tracking.c context_tracking: Switch to new static_branch API 2015-11-24 09:56:43 +01:00
cpu.c sched/hotplug: Make activate() the last hotplug step 2016-05-06 14:58:25 +02:00
cpu_pm.c kernel/cpu_pm: fix cpu_cluster_pm_exit comment 2015-09-03 02:42:20 +02:00
cpuset.c cpuset: use static key better and convert to new API 2016-05-19 19:12:14 -07:00
crash_dump.c
cred.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
delayacct.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
dma.c
elfcore.c
exec_domain.c
exit.c sched/api: Introduce task_rcu_dereference() and try_get_task_struct() 2016-06-03 09:18:57 +02:00
extable.c kernel/extable.c: remove duplicated include 2015-09-10 13:29:01 -07:00
fork.c Fix build break in fork.c when THREAD_SIZE < PAGE_SIZE 2016-06-25 06:01:28 -07:00
freezer.c
futex.c futex: Calculate the futex key based on a tail page for file-based futexes 2016-06-08 19:23:54 +02:00
futex_compat.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-01-20 17:09:18 -08:00
groups.c
hung_task.c kernel/hung_task.c: use timeout diff when timeout is updated 2016-03-22 15:36:02 -07:00
irq_work.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
jump_label.c locking/static_key: Fix concurrent static_key_slow_inc() 2016-06-24 08:23:16 +02:00
kallsyms.c kallsyms: add support for relative offsets in kallsyms address table 2016-03-15 16:55:16 -07:00
kcmp.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-01-20 17:09:18 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kernel/kcov: unproxify debugfs file's fops 2016-06-15 04:56:35 -07:00
kexec.c s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres() 2016-05-23 17:04:14 -07:00
kexec_core.c s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres() 2016-05-23 17:04:14 -07:00
kexec_file.c kexec: introduce a protection mechanism for the crashkernel reserved memory 2016-05-23 17:04:14 -07:00
kexec_internal.h kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE 2016-01-20 17:09:18 -08:00
kmod.c kmod: don't run async usermode helper as a child of kworker thread 2015-10-23 17:55:10 +09:00
kprobes.c perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe 2015-08-04 10:16:54 +02:00
ksysfs.c rcu: Remove TINY_RCU bloat from pointless boot parameters 2015-12-07 16:59:37 -08:00
kthread.c kernel/kthread.c:kthread_create_on_node(): clarify documentation 2015-09-04 16:54:41 -07:00
latencytop.c sched/debug: Make schedstats a runtime tunable that is disabled by default 2016-02-09 11:54:23 +01:00
Makefile ELF/MIPS build fix 2016-05-23 17:04:14 -07:00
membarrier.c sys_membarrier(): system-wide memory barrier (generic, x86) 2015-09-11 15:21:34 -07:00
memremap.c memremap: add arch specific hook for MEMREMAP_WB mappings 2016-04-04 10:26:41 +02:00
module-internal.h
module.c module: preserve Elf information for livepatch modules 2016-04-01 15:00:10 +02:00
module_signing.c KEYS: Move the point of trust determination to __key_link() 2016-04-11 22:43:43 +01:00
notifier.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 08:40:25 -07:00
nsproxy.c cgroup: introduce cgroup namespaces 2016-02-16 13:04:58 -05:00
padata.c kernel/padata.c: hide unused functions 2016-05-19 19:12:14 -07:00
panic.c printk/nmi: flush NMI messages on the system panic 2016-05-20 17:58:30 -07:00
params.c Nothing exciting, minor tweaks and cleanups. 2015-11-09 15:53:39 -08:00
pid.c remove lots of IS_ERR_VALUE abuses 2016-05-27 15:26:11 -07:00
pid_namespace.c
profile.c profile: hide unused functions when !CONFIG_PROC_FS 2016-03-22 15:36:02 -07:00
ptrace.c ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock 2016-03-22 15:36:02 -07:00
range.c
reboot.c kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
relay.c kernel/relay.c: fix potential memory leak 2016-06-09 14:23:11 -07:00
resource.c /proc/iomem: only expose physical resource addresses to privileged users 2016-04-14 12:56:09 -07:00
seccomp.c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-05-19 10:02:26 -07:00
signal.c kernel/signal.c: convert printk(KERN_<LEVEL> ...) to pr_<level>(...) 2016-05-23 17:04:14 -07:00
smp.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 13:50:29 -07:00
smpboot.c cpu/hotplug: Unpark smpboot threads from the state machine 2016-03-01 20:36:56 +01:00
smpboot.h cpu/hotplug: Create hotplug threads 2016-03-01 20:36:56 +01:00
softirq.c arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
stacktrace.c
stop_machine.c kernel/stop_machine.c: remove CONFIG_SMP dependencies 2016-01-16 11:17:24 -08:00
sys.c prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable 2016-05-23 17:04:14 -07:00
sys_ni.c vfs: add copy_file_range syscall and vfs helper 2015-12-01 14:00:53 -05:00
sysctl.c Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-05-25 17:05:40 -07:00
sysctl_binary.c kernel/sysctl_binary.c: use generic UUID library 2016-05-20 17:58:30 -07:00
task_work.c task_work: remove fifo ordering guarantee 2015-09-05 13:46:58 -07:00
taskstats.c taskstats: use the libnl API to align nlattr on 64-bit 2016-04-23 20:13:25 -04:00
test_kprobes.c
torture.c rcutorture: Dump trace buffer upon shutdown 2016-04-21 13:47:04 -07:00
tracepoint.c kernel/...: convert pr_warning to pr_warn 2016-03-22 15:36:02 -07:00
tsacct.c time, acct: Drop irq save & restore from __acct_update_integrals() 2016-02-29 09:53:09 +01:00
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c kernel/*: switch to memdup_user_nul() 2016-01-04 10:27:55 -05:00
utsname.c
utsname_sysctl.c
watchdog.c watchdog: don't run proc_watchdog_update if new value is same as old 2016-03-17 15:09:34 -07:00
workqueue.c debugobjects: insulate non-fixup logic related to static obj from fixup callbacks 2016-05-19 19:12:14 -07:00
workqueue_internal.h sched/core: Get rid of 'cpu' argument in wq_worker_sleeping() 2016-03-02 10:28:47 -05:00