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Alexei Starovoitov 7e3811cb99 selftests/bpf: Convert profiler.c to bpf_cmp.
Convert profiler[123].c to "volatile compare" to compare barrier_var() approach vs bpf_cmp_likely() vs bpf_cmp_unlikely().

bpf_cmp_unlikely() produces correct code, but takes much longer to verify:

./veristat -C -e prog,insns,states before after_with_unlikely
Program                               Insns (A)  Insns (B)  Insns       (DIFF)  States (A)  States (B)  States     (DIFF)
------------------------------------  ---------  ---------  ------------------  ----------  ----------  -----------------
kprobe__proc_sys_write                     1603      19606  +18003 (+1123.08%)         123        1678  +1555 (+1264.23%)
kprobe__vfs_link                          11815      70305   +58490 (+495.05%)         971        4967   +3996 (+411.53%)
kprobe__vfs_symlink                        5464      42896   +37432 (+685.07%)         434        3126   +2692 (+620.28%)
kprobe_ret__do_filp_open                   5641      44578   +38937 (+690.25%)         446        3162   +2716 (+608.97%)
raw_tracepoint__sched_process_exec         2770      35962  +33192 (+1198.27%)         226        3121  +2895 (+1280.97%)
raw_tracepoint__sched_process_exit         1526       2135      +609 (+39.91%)         133         208      +75 (+56.39%)
raw_tracepoint__sched_process_fork          265        337       +72 (+27.17%)          19          24       +5 (+26.32%)
tracepoint__syscalls__sys_enter_kill      18782     140407  +121625 (+647.56%)        1286       12176  +10890 (+846.81%)

bpf_cmp_likely() is equivalent to barrier_var():

./veristat -C -e prog,insns,states before after_with_likely
Program                               Insns (A)  Insns (B)  Insns   (DIFF)  States (A)  States (B)  States (DIFF)
------------------------------------  ---------  ---------  --------------  ----------  ----------  -------------
kprobe__proc_sys_write                     1603       1663    +60 (+3.74%)         123         127    +4 (+3.25%)
kprobe__vfs_link                          11815      12090   +275 (+2.33%)         971         971    +0 (+0.00%)
kprobe__vfs_symlink                        5464       5448    -16 (-0.29%)         434         426    -8 (-1.84%)
kprobe_ret__do_filp_open                   5641       5739    +98 (+1.74%)         446         446    +0 (+0.00%)
raw_tracepoint__sched_process_exec         2770       2608   -162 (-5.85%)         226         216   -10 (-4.42%)
raw_tracepoint__sched_process_exit         1526       1526     +0 (+0.00%)         133         133    +0 (+0.00%)
raw_tracepoint__sched_process_fork          265        265     +0 (+0.00%)          19          19    +0 (+0.00%)
tracepoint__syscalls__sys_enter_kill      18782      18970   +188 (+1.00%)        1286        1286    +0 (+0.00%)
kprobe__proc_sys_write                     2700       2809   +109 (+4.04%)         107         109    +2 (+1.87%)
kprobe__vfs_link                          12238      12366   +128 (+1.05%)         267         269    +2 (+0.75%)
kprobe__vfs_symlink                        7139       7365   +226 (+3.17%)         167         175    +8 (+4.79%)
kprobe_ret__do_filp_open                   7264       7070   -194 (-2.67%)         180         182    +2 (+1.11%)
raw_tracepoint__sched_process_exec         3768       3453   -315 (-8.36%)         211         199   -12 (-5.69%)
raw_tracepoint__sched_process_exit         3138       3138     +0 (+0.00%)          83          83    +0 (+0.00%)
raw_tracepoint__sched_process_fork          265        265     +0 (+0.00%)          19          19    +0 (+0.00%)
tracepoint__syscalls__sys_enter_kill      26679      24327  -2352 (-8.82%)        1067        1037   -30 (-2.81%)
kprobe__proc_sys_write                     1833       1833     +0 (+0.00%)         157         157    +0 (+0.00%)
kprobe__vfs_link                           9995      10127   +132 (+1.32%)         803         803    +0 (+0.00%)
kprobe__vfs_symlink                        5606       5672    +66 (+1.18%)         451         451    +0 (+0.00%)
kprobe_ret__do_filp_open                   5716       5782    +66 (+1.15%)         462         462    +0 (+0.00%)
raw_tracepoint__sched_process_exec         3042       3042     +0 (+0.00%)         278         278    +0 (+0.00%)
raw_tracepoint__sched_process_exit         1680       1680     +0 (+0.00%)         146         146    +0 (+0.00%)
raw_tracepoint__sched_process_fork          299        299     +0 (+0.00%)          25          25    +0 (+0.00%)
tracepoint__syscalls__sys_enter_kill      18372      18372     +0 (+0.00%)        1558        1558    +0 (+0.00%)

default (mcpu=v3), no_alu32, cpuv4 have similar differences.

Note one place where bpf_nop_mov() is used to workaround the verifier lack of link
between the scalar register and its spill to stack.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231226191148.48536-7-alexei.starovoitov@gmail.com
History 2024-01-03 11:08:23 -08:00
arch net/sched: Remove CONFIG_NET_ACT_IPT from default configs 2024-01-02 12:41:16 +00:00
block block-6.7-2023-12-01 2023-12-02 06:39:30 +09:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression in ahash and hides the Kconfig sub-options for the jitter RNG. 2023-11-09 17:04:58 -08:00
Documentation dt-bindings: net: renesas,etheravb: Document RZ/G3S support 2024-01-02 14:19:56 -08:00
drivers ppp: Fix spelling typo in comment in ppp_async_encode() 2024-01-02 16:26:09 -08:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-12-21 22:17:23 +01:00
include net: ethtool: add a NO_CHANGE uAPI for new RXFH's input_xfrm 2024-01-02 16:00:06 -08:00
init As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
io_uring io_uring/cmd: fix breakage in SOCKET_URING_OP_SIOC* implementation 2023-12-14 16:52:13 -07:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel bpf: Simplify checking size of helper accesses 2024-01-03 10:37:56 -08:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-12-21 22:17:23 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-12-21 22:17:23 +01:00
net net/sched: cls_api: complement tcf_tfilter_dump_policy 2024-01-03 11:54:39 +00:00
rust net: phy: add Rust Asix PHY driver 2023-12-15 09:35:50 +00:00
samples samples/bpf: Use %lu format specifier for unsigned long values 2023-12-20 15:28:59 +01:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-12-14 17:14:41 -08:00
security Revert BPF token-related functionality 2023-12-19 08:23:03 -08:00
sound ALSA: hda/tas2781: reset the amp before component_add 2023-12-14 12:04:38 +01:00
tools selftests/bpf: Convert profiler.c to bpf_cmp. 2024-01-03 11:08:23 -08:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt Revert "KVM: Prevent module exit until all VMs are freed" 2023-12-01 08:12:30 -08:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap mailmap: add entries for Geliang Tang 2023-12-17 20:54:22 +00:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: drop Antti Palosaari 2023-12-06 16:12:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS octeon_ep_vf: update MAINTAINERS 2024-01-02 14:19:54 +00:00
Makefile Linux 6.7-rc6 2023-12-17 15:19:28 -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.