linux_dsm_epyc7002/kernel/bpf
Song Liu d46edd671a bpf: Sharing bpf runtime stats with BPF_ENABLE_STATS
Currently, sysctl kernel.bpf_stats_enabled controls BPF runtime stats.
Typical userspace tools use kernel.bpf_stats_enabled as follows:

  1. Enable kernel.bpf_stats_enabled;
  2. Check program run_time_ns;
  3. Sleep for the monitoring period;
  4. Check program run_time_ns again, calculate the difference;
  5. Disable kernel.bpf_stats_enabled.

The problem with this approach is that only one userspace tool can toggle
this sysctl. If multiple tools toggle the sysctl at the same time, the
measurement may be inaccurate.

To fix this problem while keep backward compatibility, introduce a new
bpf command BPF_ENABLE_STATS. On success, this command enables stats and
returns a valid fd. BPF_ENABLE_STATS takes argument "type". Currently,
only one type, BPF_STATS_RUN_TIME, is supported. We can extend the
command to support other types of stats in the future.

With BPF_ENABLE_STATS, user space tool would have the following flow:

  1. Get a fd with BPF_ENABLE_STATS, and make sure it is valid;
  2. Check program run_time_ns;
  3. Sleep for the monitoring period;
  4. Check program run_time_ns again, calculate the difference;
  5. Close the fd.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200430071506.1408910-2-songliubraving@fb.com
2020-05-01 10:36:32 -07:00
..
arraymap.c bpf: Add lookup and update batch ops to arraymap 2020-01-15 14:00:35 -08:00
bpf_lru_list.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
bpf_lru_list.h bpf: Fix a typo "inacitve" -> "inactive" 2020-04-06 21:54:10 +02:00
bpf_lsm.c bpf: lsm: Implement attach, detach and execution 2020-03-30 01:34:00 +02:00
bpf_struct_ops_types.h bpf: tcp: Support tcp_congestion_ops in bpf 2020-01-09 08:46:18 -08:00
bpf_struct_ops.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-25 18:58:11 -07:00
btf.c bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link 2020-04-28 17:27:08 -07:00
cgroup.c bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link 2020-04-28 17:27:08 -07:00
core.c bpf: add bpf_ktime_get_boot_ns() 2020-04-26 09:43:05 -07:00
cpumap.c cpumap: Avoid warning when CONFIG_DEBUG_PER_CPU_MAPS is enabled 2020-04-20 18:38:04 -07:00
devmap.c xdp: export the DEV_MAP_BULK_SIZE macro 2020-04-22 20:11:29 -07:00
disasm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
disasm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
dispatcher.c bpf: Remove bpf_image tree 2020-03-13 12:49:52 -07:00
hashtab.c bpf: Replace zero-length array with flexible-array member 2020-02-28 01:21:02 +01:00
helpers.c bpf: add bpf_ktime_get_boot_ns() 2020-04-26 09:43:05 -07:00
inode.c bpf: Introduce pinnable bpf_link abstraction 2020-03-02 22:06:27 -08:00
local_storage.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-22 09:54:33 -08:00
lpm_trie.c bpf: Replace zero-length array with flexible-array member 2020-02-28 01:21:02 +01:00
Makefile bpf: Introduce BPF_PROG_TYPE_LSM 2020-03-30 01:34:00 +02:00
map_in_map.c bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS 2020-01-09 08:46:18 -08:00
map_in_map.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
offload.c bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill 2020-02-17 16:53:49 +01:00
percpu_freelist.c bpf: Dont iterate over possible CPUs with interrupts disabled 2020-02-24 16:18:20 -08:00
percpu_freelist.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
queue_stack_maps.c bpf: move memory size checks to bpf_map_charge_init() 2019-05-31 16:52:56 -07:00
reuseport_array.c net: Generate reuseport group ID on group creation 2020-02-21 22:29:45 +01:00
stackmap.c bpf/stackmap: Dont trylock mmap_sem with PREEMPT_RT and interrupts disabled 2020-02-24 16:20:10 -08:00
syscall.c bpf: Sharing bpf runtime stats with BPF_ENABLE_STATS 2020-05-01 10:36:32 -07:00
sysfs_btf.c bpf: Support llvm-objcopy for vmlinux BTF 2020-03-19 12:32:38 +01:00
tnum.c bpf: Verifier, do explicit ALU32 bounds tracking 2020-03-30 14:59:53 -07:00
trampoline.c bpf: lsm: Implement attach, detach and execution 2020-03-30 01:34:00 +02:00
verifier.c bpf: Allow bpf_map_lookup_elem for SOCKMAP and SOCKHASH 2020-04-29 23:30:59 +02:00
xskmap.c xsk: Make xskmap flush_list common for all map instances 2019-12-19 21:09:43 -08:00