linux/kernel
Steven Rostedt 7d137e604a fgraph: Remove unnecessary disabling of interrupts and recursion
The function graph tracer disables interrupts as well as prevents
recursion via NMIs when recording the graph tracer code. There's no reason
to do this today. That disabling goes back to 2008 when the function graph
tracer was first introduced and recursion protection wasn't part of the
code.

Today, there's no reason to disable interrupts or prevent the code from
recursing as the infrastructure can easily handle it.

Before this change:

~# echo function_graph > /sys/kernel/tracing/current_tracer
~# perf stat -r 10 ./hackbench 10
Time: 4.240
Time: 4.236
Time: 4.106
Time: 4.014
Time: 4.314
Time: 3.830
Time: 4.063
Time: 4.323
Time: 3.763
Time: 3.727

 Performance counter stats for '/work/c/hackbench 10' (10 runs):

         33,937.20 msec task-clock                       #    7.008 CPUs utilized               ( +-  1.85% )
            18,220      context-switches                 #  536.874 /sec                        ( +-  6.41% )
               624      cpu-migrations                   #   18.387 /sec                        ( +-  9.07% )
            11,319      page-faults                      #  333.528 /sec                        ( +-  1.97% )
    76,657,643,617      cycles                           #    2.259 GHz                         ( +-  0.40% )
   141,403,302,768      instructions                     #    1.84  insn per cycle              ( +-  0.37% )
    25,518,463,888      branches                         #  751.932 M/sec                       ( +-  0.35% )
       156,151,050      branch-misses                    #    0.61% of all branches             ( +-  0.63% )

            4.8423 +- 0.0892 seconds time elapsed  ( +-  1.84% )

After this change:

~# echo function_graph > /sys/kernel/tracing/current_tracer
~# perf stat -r 10 ./hackbench 10
Time: 3.340
Time: 3.192
Time: 3.129
Time: 2.579
Time: 2.589
Time: 2.798
Time: 2.791
Time: 2.955
Time: 3.044
Time: 3.065

 Performance counter stats for './hackbench 10' (10 runs):

         24,416.30 msec task-clock                       #    6.996 CPUs utilized               ( +-  2.74% )
            16,764      context-switches                 #  686.590 /sec                        ( +-  5.85% )
               469      cpu-migrations                   #   19.208 /sec                        ( +-  6.14% )
            11,519      page-faults                      #  471.775 /sec                        ( +-  1.92% )
    53,895,628,450      cycles                           #    2.207 GHz                         ( +-  0.52% )
   105,552,664,638      instructions                     #    1.96  insn per cycle              ( +-  0.47% )
    17,808,672,667      branches                         #  729.376 M/sec                       ( +-  0.48% )
       133,075,435      branch-misses                    #    0.75% of all branches             ( +-  0.59% )

             3.490 +- 0.112 seconds time elapsed  ( +-  3.22% )

Also removed unneeded "unlikely()" around the retaddr code.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/20241223184941.204074053@goodmis.org
Fixes: 9cd2992f2d ("fgraph: Have set_graph_notrace only affect function_graph tracer") # Performance only
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-12-23 20:43:55 -05:00
..
bpf bpf: Fix bpf_get_smp_processor_id() on !CONFIG_SMP 2024-12-17 16:09:24 -08:00
cgroup cgroup: Changes for v6.13 2024-11-20 09:54:49 -08:00
configs configs/debug: make sure PROVE_RCU_LIST=y takes effect 2024-10-28 10:21:09 -07:00
debug kdb: fix ctrl+e/a/f/b/d/p/n broken in keyboard mode 2024-11-18 15:20:22 +00:00
dma dma-debug: fix physical address calculation for struct dma_debug_entry 2024-11-28 10:19:16 +01:00
entry sched: Add TIF_NEED_RESCHED_LAZY infrastructure 2024-11-05 12:55:37 +01:00
events - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
futex futex: fix user access on powerpc 2024-12-09 10:00:25 -08:00
gcov gcov: add support for GCC 14 2024-06-15 10:43:06 -07:00
irq genirq/proc: Add missing space separator back 2024-12-03 14:59:34 +01:00
kcsan kcsan: Remove redundant call of kallsyms_lookup_name() 2024-10-14 16:44:56 +02:00
livepatch livepatch: Replace snprintf() with sysfs_emit() 2024-07-02 16:56:18 +02:00
locking locking: rtmutex: Fix wake_q logic in task_blocks_on_rt_mutex 2024-12-02 12:01:29 +01:00
module module: Convert symbol namespace to string literal 2024-12-02 11:34:44 -08:00
power The biggest change here is eliminating the awful idea that KVM had, of 2024-11-23 16:00:50 -08:00
printk printk changes for 6.13 2024-11-20 09:21:11 -08:00
rcu A set of updates for the interrupt subsystem: 2024-11-19 15:54:19 -08:00
sched - Prevent incorrect dequeueing of the deadline dlserver helper task and fix 2024-12-15 09:38:03 -08:00
time clocksource: Make negative motion detection more robust 2024-12-05 16:03:24 +01:00
trace fgraph: Remove unnecessary disabling of interrupts and recursion 2024-12-23 20:43:55 -05:00
.gitignore
acct.c kernel misc: Remove the now superfluous sentinel elements from ctl_table array 2024-04-24 09:43:53 +02:00
async.c async: Use a dedicated unbound workqueue with raised min_active 2024-02-09 11:13:59 -10:00
audit_fsnotify.c
audit_tree.c fsnotify: create a wrapper fsnotify_find_inode_mark() 2024-04-04 16:24:16 +02:00
audit_watch.c fsnotify: create a wrapper fsnotify_find_inode_mark() 2024-04-04 16:24:16 +02:00
audit.c lsm/stable-6.13 PR 20241112 2024-11-18 17:34:05 -08:00
audit.h audit: change context data from secid to lsm_prop 2024-10-11 14:34:16 -04:00
auditfilter.c audit: change context data from secid to lsm_prop 2024-10-11 14:34:16 -04:00
auditsc.c audit: workaround a GCC bug triggered by task comm changes 2024-12-04 22:57:46 -05:00
backtracetest.c backtracetest: add MODULE_DESCRIPTION() 2024-06-24 22:24:55 -07:00
bounds.c bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS 2024-04-29 08:29:29 -07:00
capability.c lsm: constify the 'target' parameter in security_capget() 2023-08-08 16:48:47 -04:00
cfi.c
compat.c
configs.c
context_tracking.c context_tracking, rcu: Rename rcu_dyntick trace event into rcu_watching 2024-08-15 21:30:43 +05:30
cpu_pm.c
cpu.c Driver core changes for 6.13-rc1 2024-11-29 11:43:29 -08:00
crash_core.c kexec/crash: no crash update when kexec in progress 2024-11-05 17:12:27 -08:00
crash_reserve.c crash: fix crash memory reserve exceed system memory bug 2024-09-01 20:43:30 -07:00
cred.c cred: Add a light version of override/revert_creds() 2024-11-11 10:45:04 +01:00
delayacct.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
dma.c
elfcorehdr.c crash: remove dependency of FA_DUMP on CRASH_DUMP 2024-02-23 17:48:22 -08:00
exec_domain.c
exit.c remove pointless includes of <linux/fdtable.h> 2024-10-07 13:34:41 -04:00
exit.h exit: add internal include file with helpers 2023-09-21 12:03:50 -06:00
extable.c
fail_function.c
fork.c fork: avoid inappropriate uprobe access to invalid mm 2024-12-18 19:04:44 -08:00
freezer.c sched/fair: Fix external p->on_rq users 2024-10-14 09:14:35 +02:00
gen_kheaders.sh kheaders: use command -v to test for existence of cpio 2024-05-30 01:13:20 +09:00
groups.c groups: Convert group_info.usage to refcount_t 2023-09-29 11:28:39 -07:00
hung_task.c hung_task: add detect count for hung tasks 2024-11-11 17:17:03 -08:00
iomem.c kernel/iomem.c: remove __weak ioremap_cache helper 2023-08-21 13:37:28 -07:00
irq_work.c
jump_label.c jump_label: Fix static_key_slow_dec() yet again 2024-09-10 11:57:27 +02:00
kallsyms_internal.h kallsyms: get rid of code for absolute kallsyms 2024-07-20 16:33:21 +09:00
kallsyms_selftest.c kallsyms: Match symbols exactly with CONFIG_LTO_CLANG 2024-08-15 09:33:35 -07:00
kallsyms_selftest.h
kallsyms.c kallsyms: Match symbols exactly with CONFIG_LTO_CLANG 2024-08-15 09:33:35 -07:00
kcmp.c get rid of ...lookup...fdget_rcu() family 2024-10-07 13:34:41 -04:00
Kconfig.freezer
Kconfig.hz
Kconfig.kexec crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32 2024-11-14 22:43:48 -08:00
Kconfig.locks
Kconfig.preempt sched: No PREEMPT_RT=y for all{yes,mod}config 2024-11-07 15:25:05 +01:00
kcov.c Updates for KCOV instrumentation on x86: 2024-09-17 12:40:34 +02:00
kexec_core.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kexec_elf.c
kexec_file.c kexec_file: fix elfcorehdr digest exclusion when CONFIG_CRASH_HOTPLUG=y 2024-09-01 17:59:01 -07:00
kexec_internal.h kexec: use atomic_try_cmpxchg_acquire() in kexec_trylock() 2024-09-01 20:43:23 -07:00
kexec.c crash: add a new kexec flag for hotplug support 2024-04-23 14:59:01 +10:00
kheaders.c
kprobes.c kprobes: Use struct_size() in __get_insn_slot() 2024-10-31 11:00:58 +09:00
ksyms_common.c
ksysfs.c profiling: remove prof_cpu_mask 2024-07-29 10:45:54 -07:00
kthread.c get rid of __get_task_comm() 2024-11-05 17:12:28 -08:00
latencytop.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
Makefile mm: move kernel/numa.c to mm/ 2024-09-03 21:15:26 -07:00
module_signature.c
notifier.c reboot: move reboot_notifier_list to kernel/reboot.c 2024-11-05 17:12:31 -08:00
nsproxy.c fdget(), trivial conversions 2024-11-03 01:28:06 -05:00
padata.c padata: Clean up in padata_do_multithreaded() 2024-11-10 11:50:54 +08:00
panic.c drm next for 6.12-rc1 2024-09-19 10:18:15 +02:00
params.c params: Fix multi-line comment style 2023-12-01 09:51:44 -08:00
pid_namespace.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
pid_sysctl.h sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
pid.c fdget(), more trivial conversions 2024-11-03 01:28:06 -05:00
profile.c profiling: remove profile=sleep support 2024-08-04 13:36:28 -07:00
ptrace.c ptrace_attach: shift send(SIGSTOP) into ptrace_set_stopped() 2024-02-22 15:38:52 -08:00
range.c
reboot.c kernel/reboot: replace sprintf() with sysfs_emit() 2024-11-11 17:17:05 -08:00
regset.c regset: use kvzalloc() for regset_get_alloc() 2024-04-25 21:07:03 -07:00
relay.c [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
resource_kunit.c resource, kunit: fix user-after-free in resource_test_region_intersects() 2024-10-09 12:47:19 -07:00
resource.c module: Convert symbol namespace to string literal 2024-12-02 11:34:44 -08:00
rseq.c
scftorture.c scftorture: Handle NULL argument passed to scf_add_to_free_list(). 2024-11-14 16:09:51 -08:00
scs.c
seccomp.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
signal.c posix-timers: Target group sigqueue to current task only if not exiting 2024-11-29 13:19:09 +01:00
smp.c locking/csd-lock: Switch from sched_clock() to ktime_get_mono_fast_ns() 2024-10-11 09:31:21 -07:00
smpboot.c kthread: add kthread_stop_put 2023-10-04 10:41:57 -07:00
smpboot.h
softirq.c softirq: Allow raising SCHED_SOFTIRQ from SMP-call-function on RT kernel 2024-12-02 12:01:27 +01:00
stackleak.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
stacktrace.c stacktrace: fix kernel-doc typo 2023-12-29 12:22:29 -08:00
static_call_inline.c x86/static-call: provide a way to do very early static-call updates 2024-12-13 09:28:32 +01:00
static_call.c
stop_machine.c rcu: Rename rcu_momentary_dyntick_idle() into rcu_momentary_eqs() 2024-08-15 21:30:42 +05:30
sys_ni.c Probes updates for v6.11: 2024-07-18 12:19:20 -07:00
sys.c arm64 updates for 6.13: 2024-11-18 18:10:37 -08:00
sysctl-test.c sysctl: Add module description to sysctl-testing 2024-06-03 15:20:37 +02:00
sysctl.c sysctl: Reorganize kerneldoc parameter names 2024-10-23 15:28:40 +02:00
task_work.c sched/core: Disable page allocation in task_tick_mm_cid() 2024-10-11 10:49:32 +02:00
taskstats.c fdget(), more trivial conversions 2024-11-03 01:28:06 -05:00
torture.c torture: Add MODULE_DESCRIPTION() 2024-05-30 15:31:38 -07:00
tracepoint.c tracing: Fix syscall tracepoint use-after-free 2024-11-01 14:37:31 -04:00
tsacct.c tsacct: replace strncpy() with strscpy() 2024-07-12 16:39:53 -07:00
ucount.c Summary 2024-11-22 20:36:11 -08:00
uid16.c
uid16.h
umh.c remove pointless includes of <linux/fdtable.h> 2024-10-07 13:34:41 -04:00
up.c smp: Change function signatures to use call_single_data_t 2023-09-13 14:59:24 +02:00
user_namespace.c user_namespace: use kmemdup_array() instead of kmemdup() for multiple allocation 2024-09-09 16:47:42 -07:00
user-return-notifier.c
user.c uidgid: make sure we fit into one cacheline 2024-09-12 12:16:09 +02:00
usermode_driver.c
utsname_sysctl.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
utsname.c
vhost_task.c vhost_task: Handle SIGKILL by flushing work and exiting 2024-05-22 08:31:15 -04:00
vmcore_info.c mm: support only one page_type per page 2024-09-03 21:15:43 -07:00
watch_queue.c fdget(), trivial conversions 2024-11-03 01:28:06 -05:00
watchdog_buddy.c
watchdog_perf.c watchdog/perf: properly initialize the turbo mode timestamp and rearm counter 2024-07-17 21:11:34 -07:00
watchdog.c - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
workqueue_internal.h workqueue: Drop the special locking rule for worker->flags and worker_pool->flags 2023-08-07 15:57:22 -10:00
workqueue.c workqueue: Reduce expensive locks for unbound workqueue 2024-11-15 06:43:39 -10:00