linux/tools/include
Dmitrii Banshchikov d055126180 bpf: Add bpf_ktime_get_coarse_ns helper
The helper uses CLOCK_MONOTONIC_COARSE source of time that is less
accurate but more performant.

We have a BPF CGROUP_SKB firewall that supports event logging through
bpf_perf_event_output(). Each event has a timestamp and currently we use
bpf_ktime_get_ns() for it. Use of bpf_ktime_get_coarse_ns() saves ~15-20
ns in time required for event logging.

bpf_ktime_get_ns():
EgressLogByRemoteEndpoint                              113.82ns    8.79M

bpf_ktime_get_coarse_ns():
EgressLogByRemoteEndpoint                               95.40ns   10.48M

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201117184549.257280-1-me@ubique.spb.ru
2020-11-18 23:25:32 +01:00
..
asm tools: Add missing stdio.h include to asm/bug.h header 2019-09-25 09:51:44 -03:00
asm-generic treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
linux perf tools: Remove broken __no_tail_call attribute 2020-11-03 08:32:15 -03:00
nolibc tool headers nolibc: add RISCV support 2019-05-08 15:48:43 +02:00
tools tools: bpf: fix license for a compat header file 2018-09-19 23:49:58 +02:00
trace/events
uapi bpf: Add bpf_ktime_get_coarse_ns helper 2020-11-18 23:25:32 +01:00
vdso tools headers: Synchronize linux/bits.h with the kernel sources 2020-04-14 11:40:05 -03:00