linux_dsm_epyc7002/kernel
Drew Richardson aabfa5f28f ftrace: Provide trace clock monotonic raw
Expose the NMI safe accessor to the monotonic raw clock to the
tracer. The mono clock was added with commit
1b3e5c0936. The advantage of the
monotonic raw clock is that it will advance more constantly than the
monotonic clock.

Imagine someone is trying to optimize a particular program to reduce
instructions executed for a given workload while minimizing the effect
on runtime. Also suppose that NTP is running and potentially making
larger adjustments to the monotonic clock. If NTP is adjusting the
monotonic clock to advance more rapidly, the program will appear to
use fewer instructions per second but run longer than if the monotonic
raw clock had been used. The total number of instructions observed
would be the same regardless of the clock source used, but how it's
attributed to time would be affected.

Conversely if NTP is adjusting the monotonic clock to advance more
slowly, the program will appear to use more instructions per second
but run more quickly. Of course there are many sources that can cause
jitter in performance measurements on modern processors, but let's
remove NTP from the list.

The monotonic raw clock can also be useful for tracing early boot,
e.g. when debugging issues with NTP.

Link: http://lkml.kernel.org/r/20150508143037.GB1276@dreric01-Precision-T1650

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Drew Richardson <drew.richardson@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-05-12 15:58:58 -04:00
..
bpf bpf: fix 64-bit divide 2015-04-27 23:11:49 -04:00
configs
debug debug: prevent entering debug mode on panic/exception. 2015-02-19 12:39:03 -06:00
events Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
gcov gcov: fix softlockups 2015-04-17 09:04:08 -04:00
irq genirq: Set IRQCHIP_SKIP_SET_WAKE flag for dummy_irq_chip 2015-04-24 20:57:06 +02:00
livepatch Merge branch 'for-4.1/core-noarch' into for-linus 2015-04-13 23:57:20 +02:00
locking lockdep: Make print_lock() robust against concurrent release 2015-04-17 09:42:14 +02:00
power Merge back earlier suspend/hibernate material for v4.1. 2015-04-10 12:01:59 +02:00
printk TTY/Serial patches for 4.1-rc1 2015-04-21 09:33:10 -07:00
rcu rcu: Control grace-period delays directly from value 2015-04-14 19:33:59 -07:00
sched Power management and ACPI fixes for v4.1-rc2 2015-04-30 14:23:31 -07:00
time Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-05-09 14:57:49 -07:00
trace ftrace: Provide trace clock monotonic raw 2015-05-12 15:58:58 -04:00
.gitignore
acct.c acct: check FMODE_CAN_WRITE 2015-04-11 22:27:55 -04:00
async.c
audit_tree.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
audit_watch.c VFS: audit: d_backing_inode() annotations 2015-04-15 15:06:55 -04:00
audit.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
audit.h Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-04-22 14:49:23 -07:00
auditfilter.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-02-11 20:07:47 -08:00
auditsc.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
backtracetest.c
bounds.c
capability.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
cgroup_freezer.c
cgroup.c cgroup: remove use of seq_printf return value 2015-04-15 16:35:25 -07:00
compat.c all arches, signal: move restart_block to struct task_struct 2015-02-12 18:54:12 -08:00
configs.c
context_tracking.c context_tracking: Export context_tracking_user_enter/exit 2015-03-09 15:43:00 +01:00
cpu_pm.c
cpu.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-14 13:36:04 -07:00
cpuset.c kernel, cpuset: remove exception for __GFP_THISNODE 2015-04-14 16:49:03 -07:00
crash_dump.c
cred.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c Remove rest of exec domains. 2015-04-12 21:03:31 +02:00
exit.c Remove execution domain support 2015-04-12 20:58:24 +02:00
extable.c ftrace/x86/extable: Add is_ftrace_trampoline() function 2014-11-19 15:25:26 -05:00
fork.c oprofile: reduce mmap_sem hold for mm->exe_file 2015-04-17 09:04:11 -04:00
freezer.c freezer: remove obsolete comments in __thaw_task() 2014-10-21 23:44:20 +02:00
futex_compat.c
futex.c Linux 34.0-rc1 2015-02-24 08:41:07 +01:00
groups.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
hung_task.c kernel/hung_task.c: change hung_task.c to use for_each_process_thread() 2015-04-15 16:35:22 -07:00
irq_work.c percpu: Convert remaining __get_cpu_var uses in 3.18-rcX 2014-10-29 11:18:18 -04:00
jump_label.c
kallsyms.c kernel/kallsyms.c: use __seq_open_private() 2014-10-14 02:18:16 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/mcs: Better differentiate between MCS variants 2015-01-14 15:07:32 +01:00
Kconfig.preempt
kexec.c kexec: allocate the kexec control page with KEXEC_CONTROL_MEMORY_GFP 2015-04-23 16:52:01 +02:00
kmod.c usermodehelper: kill the kmod_thread_locker logic 2014-12-10 17:41:17 -08:00
kprobes.c kprobes: makes kprobes/enabled works correctly for optimized kprobes. 2015-02-13 21:21:42 -08:00
ksysfs.c
kthread.c
latencytop.c
Makefile modsign: change default key details 2015-04-30 09:35:41 -07:00
module_signing.c
module-internal.h
module.c Quentin opened a can of worms by adding extable entry checking to modpost, 2015-04-22 09:49:24 -07:00
notifier.c rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
nsproxy.c bury struct proc_ns in fs/proc 2014-12-04 14:34:54 -05:00
padata.c padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:38 -08:00
panic.c livepatch: kernel: add TAINT_LIVEPATCH 2014-12-22 15:40:48 +01:00
params.c params: handle quotes properly for values not of form foo="bar". 2015-04-15 13:31:23 +09:30
pid_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-12-16 15:53:03 -08:00
pid.c fork: report pid reservation failure properly 2015-04-17 09:04:06 -04:00
profile.c profile: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:38 -08:00
ptrace.c ptrace: ptrace_detach() can no longer race with SIGKILL 2015-04-17 09:04:06 -04:00
range.c kernel: avoid overflow in cmp_range 2015-01-17 10:02:23 +13:00
reboot.c kernel/reboot.c: add orderly_reboot for graceful reboot 2015-04-15 16:35:23 -07:00
relay.c VFS: kernel/: d_inode() annotations 2015-04-15 15:06:55 -04:00
resource.c kernel/resource.c: remove deprecated __check_region() and friends 2015-04-15 16:35:22 -07:00
seccomp.c seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO 2015-02-17 14:34:55 -08:00
signal.c signal: remove warning about using SI_TKILL in rt_[tg]sigqueueinfo 2015-04-17 09:04:06 -04:00
smp.c smp: Fix error case handling in smp_call_function_*() 2015-04-19 13:19:23 -07:00
smpboot.c smpboot: Add common code for notification from dying CPU 2015-03-11 13:20:25 -07:00
smpboot.h
softirq.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-02-09 15:24:03 -08:00
stacktrace.c stacktrace: introduce snprint_stack_trace for buffer output 2014-12-13 12:42:48 -08:00
stop_machine.c
sys_ni.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
sys.c prctl: avoid using mmap_sem for exe_file serialization 2015-04-17 09:04:07 -04:00
sysctl_binary.c kernel: add panic_on_warn 2014-12-10 17:41:10 -08:00
sysctl.c kernel/sysctl.c: detect overflows when converting to int 2015-04-17 09:04:08 -04:00
system_certificates.S
system_keyring.c
task_work.c
taskstats.c netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c groups: Consolidate the setgroups permission checks 2014-12-05 17:19:27 -06:00
up.c
user_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2014-12-17 12:31:40 -08:00
user-return-notifier.c
user.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2014-12-17 12:31:40 -08:00
utsname_sysctl.c
utsname.c copy address of proc_ns_ops into ns_common 2014-12-04 14:34:47 -05:00
watchdog.c Merge branch 'akpm' (patches from Andrew) 2015-04-14 16:49:17 -07:00
workqueue_internal.h
workqueue.c workqueue: Reorder sysfs code 2015-04-06 11:16:04 -04:00