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Namhyung Kim 88bc63d00e perf tools: Do not set exclude_guest for precise_ip 
It seems perf sets the exclude_guest bit because of Intel PEBS
implementation which uses a virtual address.  IIUC now kernel disables
PEBS when it goes to the guest mode regardless of this bit so we don't
need to set it explicitly.  At least for the other archs/vendors.

I found the commit 1342798cc1 set the exclude_guest for precise_ip
in the tool and the commit 20b279ddb3 added kernel side enforcement
which was reverted by commit a706d965dc later.

Actually it doesn't set the exclude_guest for the default event
(cycles:P) already.

  $ grep -m1 vendor /proc/cpuinfo
  vendor_id	: GenuineIntel

  $ perf record -e cycles:P true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ]

  $ perf evlist -v | tr ',' '\n' | grep -e exclude -e precise
   precise_ip: 3

But having lower 'p' modifier set the bit for some reason.

  $ perf record -e cycles:pp true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ]

  $ perf evlist -v | tr ',' '\n' | grep -e exclude -e precise
   precise_ip: 2
   exclude_guest: 1

Actually AMD IBS suffers from this because it doesn't support excludes
and having this bit effectively disables new features in the current
implementation (due to the missing feature check).

  $ grep -m1 vendor /proc/cpuinfo
  vendor_id	: AuthenticAMD

  $ perf record -W -e cycles:p -vv true 2>&1 | grep switching
  switching off PERF_FORMAT_LOST support
  switching off weight struct support
  switching off bpf_event
  switching off ksymbol
  switching off cloexec flag
  switching off mmap2
  switching off exclude_guest, exclude_host

By not setting exclude_guest, we can fix this inconsistency and the
troubles.

Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Acked-by: Kan Liang <kan.liang@linux.intel.com>
Cc: James Clark <james.clark@arm.com>
Cc: Atish Patra <atishp@atishpatra.org>
Cc: Mingwei Zhang <mizhang@google.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20241016062359.264929-5-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2024-10-22 09:52:11 -07:00
arch powerpc fixes for 6.12 #4 2024-10-12 17:16:21 -07:00
block block-6.12-20241004 2024-10-04 10:43:44 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
Documentation Devicetree fixes for v6.12, part 1: 2024-10-11 16:07:15 -07:00
drivers USB fixes for 6.12-rc3 2024-10-13 09:21:36 -07:00
fs two fixes for Windows symlink handling 2024-10-13 10:52:39 -07:00
include NFS Client Bugfixes for Linux 6.12-rc 2024-10-11 15:37:15 -07:00
init cfi: encode cfi normalized integers + kasan/gcov bug in Kconfig 2024-09-26 21:27:27 +02:00
io_uring io_uring/rw: allow pollable non-blocking attempts for !FMODE_NOWAIT 2024-10-06 20:58:53 -06:00
ipc struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
kernel RCU fix for v6.12 2024-10-11 14:42:27 -07:00
lib slab fixes for 6.12-rc1 2024-10-04 12:05:39 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: zswap: delete comments for "value" member of 'struct zswap_entry'. 2024-10-09 12:47:19 -07:00
net USB fixes for 6.12-rc3 2024-10-13 09:21:36 -07:00
rust Driver core fix for 6.12-rc3 2024-10-13 09:10:52 -07:00
samples [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
scripts kbuild: deb-pkg: Remove blank first line from maint scripts 2024-10-07 02:36:38 +09:00
security bcachefs: do not use PF_MEMALLOC_NORECLAIM 2024-10-09 12:47:18 -07:00
sound sound fixes for 6.12-rc2 2024-10-04 11:29:46 -07:00
tools perf tools: Do not set exclude_guest for precise_ip 2024-10-22 09:52:11 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt x86: 2024-09-28 09:20:14 -07:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap Driver core fix for 6.12-rc3 2024-10-13 09:10:52 -07:00
.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 CREDITS: sort alphabetically by name 2024-10-09 12:47:19 -07:00
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 ata fixes for 6.12-rc3 2024-10-11 11:18:31 -07:00
Makefile Linux 6.12-rc3 2024-10-13 14:33:32 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

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 reStructuredText 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.