linux_dsm_epyc7002/kernel
Tom Zanussi 02205a6752 tracing: Add support for 'field variables'
Users should be able to directly specify event fields in hist trigger
'actions' rather than being forced to explicitly create a variable for
that purpose.

Add support allowing fields to be used directly in actions, which
essentially does just that - creates 'invisible' variables for each
bare field specified in an action.  If a bare field refers to a field
on another (matching) event, it even creates a special histogram for
the purpose (since variables can't be defined on an existing histogram
after histogram creation).

Here's a simple example that demonstrates both.  Basically the
onmatch() action creates a list of variables corresponding to the
parameters of the synthetic event to be generated, and then uses those
values to generate the event.  So for the wakeup_latency synthetic
event 'call' below the first param, $wakeup_lat, is a variable defined
explicitly on sched_switch, where 'next_pid' is just a normal field on
sched_switch, and prio is a normal field on sched_waking.

Since the mechanism works on variables, those two normal fields just
have 'invisible' variables created internally for them.  In the case of
'prio', which is on another event, we actually need to create an
additional hist trigger and define the invisible variable on that, since
once a hist trigger is defined, variables can't be added to it later.

  echo 'wakeup_latency u64 lat; pid_t pid; int prio' >>
       /sys/kernel/debug/tracing/synthetic_events

  echo 'hist:keys=pid:ts0=common_timestamp.usecs >>
       /sys/kernel/debug/tracing/events/sched/sched_waking/trigger

echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:
      onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,prio)
            >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger

Link: http://lkml.kernel.org/r/8e8dcdac1ea180ed7a3689e1caeeccede9dc42b3.1516069914.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-03-10 16:05:59 -05:00
..
bpf bpf: fix rcu lockdep warning for lpm_trie map_free callback 2018-02-22 21:29:12 +01:00
cgroup kernel/cpuset: current_cpuset_is_being_rebound can be boolean 2018-02-06 18:32:47 -08:00
configs KVM changes for 4.16 2018-02-10 13:16:35 -08:00
debug
events vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
gcov
irq genirq/matrix: Handle CPU offlining proper 2018-02-22 22:05:43 +01:00
livepatch Merge branch 'for-4.16/remove-immediate' into for-linus 2018-01-31 16:36:38 +01:00
locking locking/qspinlock: Ensure node->count is updated before initialising node 2018-02-13 14:50:14 +01:00
power x86/power: Fix swsusp_arch_resume prototype 2018-02-02 23:33:50 +01:00
printk Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk 2018-03-01 10:06:39 -08:00
rcu SCSI misc on 20180131 2018-01-31 11:23:28 -08:00
sched sched/cpufreq: Remove unused SUGOV_KTHREAD_PRIORITY macro 2018-02-13 13:04:03 +01:00
time timers: Forward timer base before migrating timers 2018-02-28 23:34:33 +01:00
trace tracing: Add support for 'field variables' 2018-03-10 16:05:59 -05:00
.gitignore
acct.c
async.c kernel/async.c: revert "async: simplify lowest_in_progress()" 2018-02-06 18:32:44 -08:00
audit_fsnotify.c
audit_tree.c
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
compat.c cpumask: make cpumask_size() return "unsigned int" 2018-02-06 18:32:45 -08:00
configs.c
context_tracking.c
cpu_pm.c
cpu.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c
extable.c extable: Make init_kernel_text() global 2018-02-21 16:54:06 +01:00
fail_function.c
fork.c include/linux/sched/mm.h: re-inline mmdrop() 2018-02-21 15:35:42 -08:00
freezer.c
futex_compat.c
futex.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
groups.c
hung_task.c
irq_work.c
jump_label.c extable: Make init_kernel_text() global 2018-02-21 16:54:06 +01:00
kallsyms.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk 2018-02-01 13:36:15 -08:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: detect double association with a single task 2018-02-06 18:32:46 -08:00
kexec_core.c
kexec_file.c
kexec_internal.h
kexec.c
kmod.c
kprobes.c kprobes: Propagate error from disarm_kprobe_ftrace() 2018-02-16 09:12:58 +01:00
ksysfs.c
kthread.c
latencytop.c
Makefile
memremap.c memremap: fix softlockup reports at teardown 2018-03-02 19:34:50 -08:00
module_signing.c
module-internal.h
module.c Modules updates for v4.16 2018-02-07 14:29:34 -08:00
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
profile.c
ptrace.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
range.c
reboot.c
relay.c kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE 2018-02-21 15:35:43 -08:00
resource.c Merge branch 'akpm' (patches from Andrew) 2018-02-06 22:15:42 -08:00
seccomp.c - Fix seccomp GET_METADATA to deal with field sizes correctly (Tycho Andersen) 2018-02-22 10:50:24 -08:00
signal.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2018-01-31 13:02:18 -08:00
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl_binary.c
sysctl.c pipe: reject F_SETPIPE_SZ with size over UINT_MAX 2018-02-06 18:32:47 -08:00
task_work.c
taskstats.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
umh.c
up.c
user_namespace.c
user-return-notifier.c
user.c efivarfs: Limit the rate for non-root to read files 2018-02-22 10:21:02 -08:00
utsname_sysctl.c
utsname.c
watchdog_hld.c
watchdog.c
workqueue_internal.h
workqueue.c Fixes for 4.16. I contains fixes for deadlock on runtime suspend on few 2018-02-22 08:39:26 +10:00