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Andrii Nakryiko d41bc48bfa selftests/bpf: Add uprobe triggering overhead benchmarks
Add benchmark to measure overhead of uprobes and uretprobes. Also have
a baseline (no uprobe attached) benchmark.

On my dev machine, baseline benchmark can trigger 130M user_target()
invocations. When uprobe is attached, this falls to just 700K. With
uretprobe, we get down to 520K:

  $ sudo ./bench trig-uprobe-base -a
  Summary: hits  131.289 ± 2.872M/s

  # UPROBE
  $ sudo ./bench -a trig-uprobe-without-nop
  Summary: hits    0.729 ± 0.007M/s

  $ sudo ./bench -a trig-uprobe-with-nop
  Summary: hits    1.798 ± 0.017M/s

  # URETPROBE
  $ sudo ./bench -a trig-uretprobe-without-nop
  Summary: hits    0.508 ± 0.012M/s

  $ sudo ./bench -a trig-uretprobe-with-nop
  Summary: hits    0.883 ± 0.008M/s

So there is almost 2.5x performance difference between probing nop vs
non-nop instruction for entry uprobe. And 1.7x difference for uretprobe.

This means that non-nop uprobe overhead is around 1.4 microseconds for uprobe
and 2 microseconds for non-nop uretprobe.

For nop variants, uprobe and uretprobe overhead is down to 0.556 and
1.13 microseconds, respectively.

For comparison, just doing a very low-overhead syscall (with no BPF
programs attached anywhere) gives:

  $ sudo ./bench trig-base -a
  Summary: hits    4.830 ± 0.036M/s

So uprobes are about 2.67x slower than pure context switch.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211116013041.4072571-1-andrii@kernel.org
2021-11-16 14:46:49 +01:00
arch bpf: Change value of MAX_TAIL_CALL_CNT from 32 to 33 2021-11-16 14:03:15 +01:00
block for-5.16/drivers-2021-11-09 2021-11-09 11:24:08 -08:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-11-12 12:35:46 -08:00
Documentation Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-11-15 08:49:23 -08:00
drivers Revert "Merge branch 'mctp-i2c-driver'" 2021-11-15 07:53:10 -08:00
fs Networking fixes for 5.16-rc1, including fixes from bpf, can 2021-11-11 09:49:36 -08:00
include bpf: Change value of MAX_TAIL_CALL_CNT from 32 to 33 2021-11-16 14:03:15 +01:00
init mm: allow only SLUB on PREEMPT_RT 2021-11-11 09:34:35 -08:00
ipc ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL 2021-11-09 10:02:53 -08:00
kernel bpf: Change value of MAX_TAIL_CALL_CNT from 32 to 33 2021-11-16 14:03:15 +01:00
lib bpf: Change value of MAX_TAIL_CALL_CNT from 32 to 33 2021-11-16 14:03:15 +01:00
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samples Add gitignore file for samples/fanotify/ subdirectory 2021-11-07 11:19:24 -08:00
scripts Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
security + Features 2021-11-11 14:47:32 -08:00
sound sound fixes for 5.16-rc1 2021-11-12 12:17:30 -08:00
tools selftests/bpf: Add uprobe triggering overhead benchmarks 2021-11-16 14:46:49 +01:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt kvm: irqfd: avoid update unmodified entries of the routing 2021-09-30 04:27:10 -04:00
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.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2021-11-12 11:53:16 -08:00
Makefile Kbuild updates for v5.16 2021-11-08 09:15:45 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.