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Linus Torvalds 473f6c8f43 perf tools updates for v7.3
perf c2c:
 
  - Add 'function view' in perf c2c report TUI (switched by pressing 'TAB'
    in the cacheline view) to organize samples around functions rather than
    cachelines in 3-level hierarchy:
 
      Level 1: Read-side function (sorted by estimated Cycles %)
      Level 2:   Contending writer functions (sorted by Store count)
      Level 3:     Shared cacheline addresses
 
    Users can navigate the entries and fold/unfold using 'e' key.  An example
    output would look like below:
 
     Shared Data Functions Table     (19 entries, sorted on Cycles %)
        Cycles    Store
             %    count  Function / Contending function / Cacheline
     ----------------------------------------------------------------------
     +  35.67%      876  + [k] cpupri_set
     +  24.31%      424  + [k] pull_rt_task
     -  16.53%      555  - [k] dequeue_pushable_task
                    145    - [k] pull_rt_task
                    145        0xff2d0082809da080
                    139    - [k] enqueue_pushable_task
                     70        0xff2d00a2071f9640
                     69        0xff2d0082809da000
 
 python module support:
 
  - Extend "perf" python module so that it can be fully functional.  The goal
    is to run scripts directly, not by 'perf script' command.  This would give
    better performance as well as more control to build standalone programs
    with UI.
 
  - Add LiveSession helper (perf_live.py) to enable live event collection
    directly from Python using perf.evlist and perf.parse_events.
 
 perf stat:
 
  - Add --hide-zero-events option to suppress zero-count events.
  - Reject conflicting --field-separator and --json-output options.
  - Fix duplicate event output with --for-each-cgroup.
 
 perf sched latency:
 
  - Add -H/--histogram and --hist-mode (log|linear) options to show scheduler
    wait latency histograms.
  - Add --time option to filter analysis by time span in 'perf sched latency'.
 
 ARM CoreSight:
 
  - Synthesize callchains for instruction samples from CoreSight trace
    using thread stack ('--itrace=g...').
  - Support call indentation ('perf script -F +callindent') to display call
    depth hierarchy on branch samples.
  - Decode ETE (Embedded Trace Extension) exception packets.
 
 Build system:
 
  - Add 'make install-build-deps' target to install required packages.
  - Parallelize JSON and metric pre-computation in jevents.py for faster builds.
 
 Vendor event/metric updates:
 
  - Add Intel Nova Lake events and update tables for existing models.
  - Update AMD Zen 5 and Zen 6 core events.
  - Update Arm64 Tegra410 metrics and PowerPC hcalls.
 
 Internal changes and fixes:
 
  - Harden trace-event and synthetic event parsing against corrupted data.
  - Fix unwinding of multi-threaded processes in libdw unwinder.
  - Fix memory leaks in various commands and python bindings.
  - Speed up 'perf test' shell tests.
 
 Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Merge tag 'perf-tools-for-v7.3-2026-08-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

Pull perf tools updates from Namhyung Kim:
 "perf c2c:

   - Add 'function view' in perf c2c report TUI (switched by pressing
     'TAB' in the cacheline view) to organize samples around functions
     rather than cachelines in 3-level hierarchy:

	Level 1: Read-side function (sorted by estimated Cycles %)
	Level 2:   Contending writer functions (sorted by Store count)
	Level 3:     Shared cacheline addresses

     Users can navigate the entries and fold/unfold using 'e' key. An
     example output would look like below:

	Shared Data Functions Table     (19 entries, sorted on Cycles %)
	   Cycles    Store
	        %    count  Function / Contending function / Cacheline
	----------------------------------------------------------------------
	+  35.67%      876  + [k] cpupri_set
	+  24.31%      424  + [k] pull_rt_task
	-  16.53%      555  - [k] dequeue_pushable_task
	               145    - [k] pull_rt_task
	               145        0xff2d0082809da080
	               139    - [k] enqueue_pushable_task
	                70        0xff2d00a2071f9640
	                69        0xff2d0082809da000

  python module support:

   - Extend "perf" python module so that it can be fully functional. The
     goal is to run scripts directly, not by 'perf script' command. This
     would give better performance as well as more control to build
     standalone programs with UI.

   - Add LiveSession helper (perf_live.py) to enable live event
     collection directly from Python using perf.evlist and
     perf.parse_events.

  perf stat:

   - Add --hide-zero-events option to suppress zero-count events
   - Reject conflicting --field-separator and --json-output options
   - Fix duplicate event output with --for-each-cgroup

  perf sched latency:

   - Add -H/--histogram and --hist-mode (log|linear) options to show
     scheduler wait latency histograms
   - Add --time option to filter analysis by time span in 'perf sched
     latency'

  ARM CoreSight:

   - Synthesize callchains for instruction samples from CoreSight trace
     using thread stack ('--itrace=g...')
   - Support call indentation ('perf script -F +callindent') to display
     call depth hierarchy on branch samples
   - Decode ETE (Embedded Trace Extension) exception packets

  Build system:

   - Add 'make install-build-deps' target to install required packages
   - Parallelize JSON and metric pre-computation in jevents.py for
     faster builds

  Vendor event/metric updates:

   - Add Intel Nova Lake events and update tables for existing models
   - Update AMD Zen 5 and Zen 6 core events
   - Update Arm64 Tegra410 metrics and PowerPC hcalls

  Internal changes and fixes:

   - Harden trace-event and synthetic event parsing against corrupted
     data
   - Fix unwinding of multi-threaded processes in libdw unwinder
   - Fix memory leaks in various commands and python bindings
   - Speed up 'perf test' shell tests"

* tag 'perf-tools-for-v7.3-2026-08-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (232 commits)
  perf vendor events arm64: Fix Tegra410 Olympus event 0x0197
  perf vendor events arm64: fix swapped MetricGroup for Tegra410 L1 prefetcher metrics
  perf evlist: Warn when 'sleep' workload is used without system-wide (-a) option
  perf c2c: document function view in perf-c2c man page
  perf c2c: add function view browser UI and cacheline detail
  perf c2c: build and finalize the function view hierarchy
  perf c2c: add function view hierarchy entry creation
  perf c2c: add function view stats merge and memory management
  perf c2c: add HPP list parsing for function view columns
  perf c2c: add column rendering for function view
  perf c2c: add function view model skeleton
  perf c2c: extract shared data structures into util/c2c.h
  perf test sample-parsing: Validate PERF_FORMAT_GROUP values without LOST
  perf dso: Replace assert with runtime check in dso__read_symbol()
  perf dso: Guard against cache underflow on short reads in dso_cache__memcpy()
  perf dso: Use stored fd error instead of stale errno in file_read() and file_size()
  perf dso: Guard close() against invalid fd in dso__decompress_kmodule_path()
  perf dso: Guard against errno==0 when dso__get_filename() returns NULL
  perf build: install-build-deps: add RHEL family devel package mapping
  perf build: Remove leftover feature tests for removed cxx and clang support
  ...
2026-08-22 08:47:50 -07:00
arch Modules changes for 7.3-rc1 2026-08-21 12:47:25 -07:00
block for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto This update includes the following changes: 2026-08-19 17:25:42 -07:00
Documentation perf tools updates for v7.3 2026-08-22 08:47:50 -07:00
drivers firewire updates for v7.3 2026-08-22 08:41:28 -07:00
fs eCryptfs updates for 7.3-rc1 2026-08-21 12:32:01 -07:00
include Modules changes for 7.3-rc1 2026-08-21 12:47:25 -07:00
init mm.git review status for mm-hotfixes-stable..mm-stable 2026-08-20 18:17:08 -07:00
io_uring for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
ipc mm.git review status for mm-hotfixes-stable..mm-stable 2026-08-20 18:17:08 -07:00
kernel livepatching changes for 7.3 2026-08-21 13:11:56 -07:00
lib drm for 7.3-rc1 2026-08-21 08:41:00 -07:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm 8 hotfixes. 5 are cc:stable. 5 are for MM. 2026-08-20 20:05:59 -07:00
net RDMA v7.3 merge window pull 2026-08-21 11:48:54 -07:00
rust Modules changes for 7.3-rc1 2026-08-21 12:47:25 -07:00
samples Modules changes for 7.3-rc1 2026-08-21 12:47:25 -07:00
scripts Modules changes for 7.3-rc1 2026-08-21 12:47:25 -07:00
security Landlock update for v7.3-rc1 2026-08-21 12:28:35 -07:00
sound mm.git review status for mm-hotfixes-stable..mm-stable 2026-08-20 18:17:08 -07:00
tools perf tools updates for v7.3 2026-08-22 08:47:50 -07:00
usr usr: Correct a spelling by changing a letter 2026-08-05 14:51:58 +02:00
virt mm: use linear_page_[index, delta]() consistently 2026-08-04 19:19:01 -07:00
.clang-format drm/bridge: rename drm_for_each_bridge_in_chain_scoped() to drm_for_each_bridge_in_chain() 2026-07-14 17:55:51 +02:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap drm for 7.3-rc1 2026-08-21 08:41:00 -07:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -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 CIFS Maintainer switch 2026-08-21 12:16:31 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Landlock update for v7.3-rc1 2026-08-21 12:28:35 -07:00
Makefile livepatching changes for 7.3 2026-08-21 13:11:56 -07:00
README README: remove out of place emdashes 2026-07-15 10:51:29 -06:00

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

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer: Getting started with kernel development
* Academic Researcher: Studying kernel internals and architecture
* Security Expert: Hardening and vulnerability analysis
* Backport/Maintenance Engineer: Maintaining stable kernels
* System Administrator: Configuring and troubleshooting
* Maintainer: Leading subsystems and reviewing patches
* Hardware Vendor: Writing drivers for new hardware
* Distribution Maintainer: Packaging kernels for distros
* AI Coding Assistant: LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst