kernel_optimize_test/kernel
Daniel Xu fff7b64355 bpf: Add bpf_read_branch_records() helper
Branch records are a CPU feature that can be configured to record
certain branches that are taken during code execution. This data is
particularly interesting for profile guided optimizations. perf has had
branch record support for a while but the data collection can be a bit
coarse grained.

We (Facebook) have seen in experiments that associating metadata with
branch records can improve results (after postprocessing). We generally
use bpf_probe_read_*() to get metadata out of userspace. That's why bpf
support for branch records is useful.

Aside from this particular use case, having branch data available to bpf
progs can be useful to get stack traces out of userspace applications
that omit frame pointers.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200218030432.4600-2-dxu@dxuuu.xyz
2020-02-19 14:37:36 -08:00
..
bpf Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-02-08 17:15:08 -08:00
cgroup Merge branch 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2020-02-10 17:07:05 -08:00
configs
debug Revert "kdb: Get rid of confusing diag msg from "rd" if current task has no regs" 2020-02-06 11:40:09 +00:00
dma lib/genalloc.c: rename addr_in_gen_pool to gen_pool_has_addr 2019-12-04 19:44:13 -08:00
events A set of fixes and improvements for the perf subsystem: 2020-02-09 12:04:09 -08:00
gcov Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-01-19 22:42:06 +01:00
irq A set of fixes for X86: 2020-02-09 12:11:12 -08:00
livepatch New tracing features: 2019-11-27 11:42:01 -08:00
locking proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
power ACPI: PM: s2idle: Avoid possible race related to the EC GPE 2020-02-11 10:11:02 +01:00
printk printk: fix exclusive_console replaying 2020-01-02 16:15:04 +01:00
rcu rcu: Forgive slow expedited grace periods at boot time 2020-01-25 12:00:40 -08:00
sched proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
time Two small fixes for the time(r) subsystem: 2020-02-09 12:00:12 -08:00
trace bpf: Add bpf_read_branch_records() helper 2020-02-19 14:37:36 -08:00
.gitignore
acct.c acct: stop using get_seconds() 2019-12-18 18:07:31 +01:00
async.c
audit_fsnotify.c
audit_tree.c
audit_watch.c audit_get_nd(): don't unlock parent too early 2019-11-10 11:56:55 -05:00
audit.c audit: Add __rcu annotation to RCU pointer 2019-12-09 15:19:03 -05:00
audit.h
auditfilter.c
auditsc.c Revert "bpf: Emit audit messages upon successful prog load and unload" 2019-11-23 09:56:02 -08:00
backtracetest.c
bounds.c
capability.c
compat.c y2038: itimer: compat handling to itimer.c 2019-11-15 14:38:30 +01:00
configs.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
context_tracking.c context_tracking: Rename context_tracking_is_enabled() => context_tracking_enabled() 2019-10-29 10:01:12 +01:00
cpu_pm.c
cpu.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-01-28 10:07:09 -08:00
crash_core.c
crash_dump.c
cred.c Merge branch 'dhowells' (patches from DavidH) 2020-01-14 09:56:31 -08:00
delayacct.c
dma.c
elfcore.c kernel/elfcore.c: include proper prototypes 2019-09-25 17:51:39 -07:00
exec_domain.c
exit.c for-linus-2020-01-03 2020-01-03 11:17:14 -08:00
extable.c bpf: Allow to resolve bpf trampoline and dispatcher in unwind 2020-01-25 07:12:40 -08:00
fail_function.c
fork.c hmm related patches for 5.6 2020-01-29 19:56:50 -08:00
freezer.c Revert "libata, freezer: avoid block device removal while system is frozen" 2019-10-06 09:11:37 -06:00
futex.c futex: Fix kernel-doc notation warning 2020-01-09 13:23:40 +01:00
gen_kheaders.sh kheaders: explain why include/config/autoconf.h is excluded from md5sum 2019-11-11 20:10:01 +09:00
groups.c
hung_task.c
iomem.c
irq_work.c irq_work: Fix IRQ_WORK_BUSY bit clearing 2019-11-15 10:48:37 +01:00
jump_label.c
kallsyms.c Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks sched/rt, locking: Use CONFIG_PREEMPTION 2019-12-08 14:37:36 +01:00
Kconfig.preempt sched/Kconfig: Fix spelling mistake in user-visible help text 2019-11-12 11:35:32 +01:00
kcov.c kcov: remote coverage support 2019-12-04 19:44:14 -08:00
kexec_core.c kexec: add machine_kexec_post_load() 2020-01-08 16:32:55 +00:00
kexec_elf.c kexec_elf: support 32 bit ELF files 2019-09-06 23:58:44 +02:00
kexec_file.c kexec: add machine_kexec_post_load() 2020-01-08 16:32:55 +00:00
kexec_internal.h kexec: add machine_kexec_post_load() 2020-01-08 16:32:55 +00:00
kexec.c kexec: add machine_kexec_post_load() 2020-01-08 16:32:55 +00:00
kheaders.c
kmod.c
kprobes.c kprobes: Fix optimize_kprobe()/unoptimize_kprobe() cancellation logic 2020-01-09 12:40:13 +01:00
ksysfs.c
kthread.c kthread: make __kthread_queue_delayed_work static 2019-10-16 09:20:58 -07:00
latencytop.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
Makefile kcov: ignore fault-inject and stacktrace 2020-01-31 10:30:41 -08:00
module_signature.c
module_signing.c
module-internal.h
module.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
notifier.c kernel/notifier.c: remove blocking_notifier_chain_cond_register() 2019-12-04 19:44:12 -08:00
nsproxy.c ns: Introduce Time Namespace 2020-01-14 12:20:48 +01:00
padata.c padata: update documentation 2019-12-11 16:37:02 +08:00
panic.c locking/refcount: Remove unused 'refcount_error_report()' function 2019-11-25 09:15:42 +01:00
params.c
pid_namespace.c fork: extend clone3() to support setting a PID 2019-11-15 23:49:22 +01:00
pid.c pid: Implement pidfd_getfd syscall 2020-01-13 21:49:36 +01:00
profile.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
ptrace.c ptrace: reintroduce usage of subjective credentials in ptrace_has_cap() 2020-01-18 13:51:39 +01:00
range.c
reboot.c
relay.c
resource.c mm/memory_hotplug.c: use PFN_UP / PFN_DOWN in walk_system_ram_range() 2019-09-24 15:54:09 -07:00
rseq.c rseq: Reject unknown flags on rseq unregister 2019-12-25 10:41:20 +01:00
seccomp.c seccomp: Check that seccomp_notif is zeroed out by the user 2020-01-02 13:03:45 -08:00
signal.c sched.h: Annotate sighand_struct with __rcu 2020-01-26 10:54:47 +01:00
smp.c smp: Remove superfluous cond_func check in smp_call_function_many_cond() 2020-01-28 15:43:00 +01:00
smpboot.c
smpboot.h
softirq.c
stackleak.c
stacktrace.c stacktrace: Get rid of unneeded '!!' pattern 2019-11-11 10:30:59 +01:00
stop_machine.c stop_machine: Make stop_cpus() static 2020-01-17 10:19:21 +01:00
sys_ni.c y2038: allow disabling time32 system calls 2019-11-15 14:38:30 +01:00
sys.c prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim 2020-01-28 10:09:51 +01:00
sysctl_binary.c sysctl: Remove the sysctl system call 2019-11-26 13:03:56 -06:00
sysctl-test.c kunit: allow kunit tests to be loaded as a module 2020-01-09 16:42:29 -07:00
sysctl.c rcu: Make PREEMPT_RCU be a modifier to TREE_RCU 2019-12-09 12:37:51 -08:00
task_work.c
taskstats.c taskstats: fix data-race 2019-12-04 15:18:39 +01:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c tsacct: add 64-bit btime field 2019-12-18 18:07:31 +01:00
ucount.c
uid16.c
uid16.h
umh.c
up.c smp/up: Make smp_call_function_single() match SMP semantics 2020-02-07 15:34:12 +01:00
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog_hld.c
watchdog.c watchdog/softlockup: Enforce that timestamp is valid on boot 2020-01-17 11:19:22 +01:00
workqueue_internal.h
workqueue.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-01-28 10:07:09 -08:00