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Linus Torvalds 3a36281a17 New features:
- Support instruction latency in 'perf report', with both memory latency
   (weight) and instruction latency information, users can locate expensive load
   instructions and understand time spent in different stages.
 
 - Extend 'perf c2c' to display the number of loads which were blocked by data
   or address conflict.
 
 - Add 'perf stat' support for L2 topdown events in systems such as Intel's
   Sapphire rapids server.
 
 - Add support for PERF_SAMPLE_CODE_PAGE_SIZE in various tools, as a sort key, for instance:
 
     perf report --stdio --sort=comm,symbol,code_page_size
 
 - New 'perf daemon' command to run long running sessions while providing a way to control
   the enablement of events without restarting a traditional 'perf record' session.
 
 - Enable counting events for BPF programs in 'perf stat' just like for other
   targets (tid, cgroup, cpu, etc), e.g.:
 
       # perf stat -e ref-cycles,cycles -b 254 -I 1000
          1.487903822            115,200      ref-cycles
          1.487903822             86,012      cycles
          2.489147029             80,560      ref-cycles
          2.489147029             73,784      cycles
       ^C#
 
   The example above counts 'cycles' and 'ref-cycles' of BPF program of id 254.
   It is similar to bpftool-prog-profile command, but more flexible.
 
 - Support the new layout for PERF_RECORD_MMAP2 to carry the DSO build-id using infrastructure
   generalised from the eBPF subsystem, removing the need for traversing the perf.data file
   to collect build-ids at the end of 'perf record' sessions and helping with long running
   sessions where binaries can get replaced in updates, leading to possible mis-resolution
   of symbols.
 
 - Support filtering by hex address in 'perf script'.
 
 - Support DSO filter in 'perf script', like in other perf tools.
 
 - Add namespaces support to 'perf inject'
 
 - Add support for SDT (Dtrace Style Markers) events on ARM64.
 
 perf record:
 
 - Fix handling of eventfd() when draining a buffer in 'perf record'.
 
 - Improvements to the generation of metadata events for pre-existing threads (mmaps, comm, etc),
   speeding up the work done at the start of system wide or per CPU 'perf record' sessions.
 
 Hardware tracing:
 
 - Initial support for tracing KVM with Intel PT.
 
 - Intel PT fixes for IPC
 
 - Support Intel PT PSB (synchronization packets) events.
 
 - Automatically group aux-output events to overcome --filter syntax.
 
 - Enable PERF_SAMPLE_DATA_SRC on ARMs SPE.
 
 - Update ARM's CoreSight hardware tracing OpenCSD library to v1.0.0.
 
 perf annotate TUI:
 
 - Fix handling of 'k' ("show line number") hotkey
 
 - Fix jump parsing for C++ code.
 
 perf probe:
 
 - Add protection to avoid endless loop.
 
 cgroups:
 
 - Avoid reading cgroup mountpoint multiple times, caching it.
 
 - Fix handling of cgroup v1/v2 in mixed hierarchy.
 
 Symbol resolving:
 
 - Add OCaml symbol demangling.
 
 - Further fixes for handling PE executables when using perf with Wine and .exe/.dll files.
 
 - Fix 'perf unwind' DSO handling.
 
 - Resolve symbols against debug file first, to deal with artifacts related to LTO.
 
 - Fix gap between kernel end and module start on powerpc.
 
 Reporting tools:
 
 - The DSO filter shouldn't show samples in unresolved maps.
 
 - Improve debuginfod support in various tools.
 
 build ids:
 
 - Fix 16-byte build ids in 'perf buildid-cache', add a 'perf test' entry for that case.
 
 perf test:
 
 - Support for PERF_SAMPLE_WEIGHT_STRUCT.
 
 - Add test case for PERF_SAMPLE_CODE_PAGE_SIZE.
 
 - Shell based tests for 'perf daemon's commands ('start', 'stop, 'reconfig', 'list', etc).
 
 - ARM cs-etm 'perf test' fixes.
 
 - Add parse-metric memory bandwidth testcase.
 
 Compiler related:
 
 - Fix 'perf probe' kretprobe issue caused by gcc 11 bug when used with -fpatchable-function-entry.
 
 - Fix ARM64 build with gcc 11's -Wformat-overflow.
 
 - Fix unaligned access in sample parsing test.
 
 - Fix printf conversion specifier for IP addresses on arm64, s390 and powerpc.
 
 Arch specific:
 
 - Support exposing Performance Monitor Counter SPRs as part of extended regs on powerpc.
 
 - Add JSON 'perf stat' metrics for ARM64's imx8mp, imx8mq and imx8mn DDR, fix imx8mm ones.
 
 - Fix common and uarch events for ARM64's A76 and Ampere eMag
 
 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-tools-for-v5.12-2020-02-19' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull perf tool updates from Arnaldo Carvalho de Melo:
 "New features:

   - Support instruction latency in 'perf report', with both memory
     latency (weight) and instruction latency information, users can
     locate expensive load instructions and understand time spent in
     different stages.

   - Extend 'perf c2c' to display the number of loads which were blocked
     by data or address conflict.

   - Add 'perf stat' support for L2 topdown events in systems such as
     Intel's Sapphire rapids server.

   - Add support for PERF_SAMPLE_CODE_PAGE_SIZE in various tools, as a
     sort key, for instance:

        perf report --stdio --sort=comm,symbol,code_page_size

   - New 'perf daemon' command to run long running sessions while
     providing a way to control the enablement of events without
     restarting a traditional 'perf record' session.

   - Enable counting events for BPF programs in 'perf stat' just like
     for other targets (tid, cgroup, cpu, etc), e.g.:

        # perf stat -e ref-cycles,cycles -b 254 -I 1000
           1.487903822            115,200      ref-cycles
           1.487903822             86,012      cycles
           2.489147029             80,560      ref-cycles
           2.489147029             73,784      cycles
        ^C

     The example above counts 'cycles' and 'ref-cycles' of BPF program
     of id 254. It is similar to bpftool-prog-profile command, but more
     flexible.

   - Support the new layout for PERF_RECORD_MMAP2 to carry the DSO
     build-id using infrastructure generalised from the eBPF subsystem,
     removing the need for traversing the perf.data file to collect
     build-ids at the end of 'perf record' sessions and helping with
     long running sessions where binaries can get replaced in updates,
     leading to possible mis-resolution of symbols.

   - Support filtering by hex address in 'perf script'.

   - Support DSO filter in 'perf script', like in other perf tools.

   - Add namespaces support to 'perf inject'

   - Add support for SDT (Dtrace Style Markers) events on ARM64.

  perf record:

   - Fix handling of eventfd() when draining a buffer in 'perf record'.

   - Improvements to the generation of metadata events for pre-existing
     threads (mmaps, comm, etc), speeding up the work done at the start
     of system wide or per CPU 'perf record' sessions.

  Hardware tracing:

   - Initial support for tracing KVM with Intel PT.

   - Intel PT fixes for IPC

   - Support Intel PT PSB (synchronization packets) events.

   - Automatically group aux-output events to overcome --filter syntax.

   - Enable PERF_SAMPLE_DATA_SRC on ARMs SPE.

   - Update ARM's CoreSight hardware tracing OpenCSD library to v1.0.0.

  perf annotate TUI:

   - Fix handling of 'k' ("show line number") hotkey

   - Fix jump parsing for C++ code.

  perf probe:

   - Add protection to avoid endless loop.

  cgroups:

   - Avoid reading cgroup mountpoint multiple times, caching it.

   - Fix handling of cgroup v1/v2 in mixed hierarchy.

  Symbol resolving:

   - Add OCaml symbol demangling.

   - Further fixes for handling PE executables when using perf with Wine
     and .exe/.dll files.

   - Fix 'perf unwind' DSO handling.

   - Resolve symbols against debug file first, to deal with artifacts
     related to LTO.

   - Fix gap between kernel end and module start on powerpc.

  Reporting tools:

   - The DSO filter shouldn't show samples in unresolved maps.

   - Improve debuginfod support in various tools.

  build ids:

   - Fix 16-byte build ids in 'perf buildid-cache', add a 'perf test'
     entry for that case.

  perf test:

   - Support for PERF_SAMPLE_WEIGHT_STRUCT.

   - Add test case for PERF_SAMPLE_CODE_PAGE_SIZE.

   - Shell based tests for 'perf daemon's commands ('start', 'stop,
     'reconfig', 'list', etc).

   - ARM cs-etm 'perf test' fixes.

   - Add parse-metric memory bandwidth testcase.

  Compiler related:

   - Fix 'perf probe' kretprobe issue caused by gcc 11 bug when used
     with -fpatchable-function-entry.

   - Fix ARM64 build with gcc 11's -Wformat-overflow.

   - Fix unaligned access in sample parsing test.

   - Fix printf conversion specifier for IP addresses on arm64, s390 and
     powerpc.

  Arch specific:

   - Support exposing Performance Monitor Counter SPRs as part of
     extended regs on powerpc.

   - Add JSON 'perf stat' metrics for ARM64's imx8mp, imx8mq and imx8mn
     DDR, fix imx8mm ones.

   - Fix common and uarch events for ARM64's A76 and Ampere eMag"

* tag 'perf-tools-for-v5.12-2020-02-19' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (148 commits)
  perf buildid-cache: Don't skip 16-byte build-ids
  perf buildid-cache: Add test for 16-byte build-id
  perf symbol: Remove redundant libbfd checks
  perf test: Output the sub testing result in cs-etm
  perf test: Suppress logs in cs-etm testing
  perf tools: Fix arm64 build error with gcc-11
  perf intel-pt: Add documentation for tracing virtual machines
  perf intel-pt: Split VM-Entry and VM-Exit branches
  perf intel-pt: Adjust sample flags for VM-Exit
  perf intel-pt: Allow for a guest kernel address filter
  perf intel-pt: Support decoding of guest kernel
  perf machine: Factor out machine__idle_thread()
  perf machine: Factor out machines__find_guest()
  perf intel-pt: Amend decoder to track the NR flag
  perf intel-pt: Retain the last PIP packet payload as is
  perf intel_pt: Add vmlaunch and vmresume as branches
  perf script: Add branch types for VM-Entry and VM-Exit
  perf auxtrace: Automatically group aux-output events
  perf test: Fix unaligned access in sample parsing test
  perf tools: Support arch specific PERF_SAMPLE_WEIGHT_STRUCT processing
  ...
2021-02-22 13:59:43 -08:00
arch It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
block for-5.12/block-ipi-2021-02-21 2021-02-22 10:53:05 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-02-21 17:23:56 -08:00
Documentation \n 2021-02-22 13:17:39 -08:00
drivers It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
fs Optimization: 2021-02-22 13:29:55 -08:00
include Optimization: 2021-02-22 13:29:55 -08:00
init Scheduler updates for v5.12: 2021-02-21 12:35:04 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel kgdb patches for 5.12 2021-02-22 11:08:05 -08:00
lib \n 2021-02-22 13:25:37 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm memblock: remove return value of memblock_free_all() 2021-02-22 13:01:23 -08:00
net Optimization: 2021-02-22 13:29:55 -08:00
samples It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
scripts It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
security Merge branch 'work.audit' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-02-22 13:05:30 -08:00
sound sound updates for 5.12 2021-02-21 14:21:35 -08:00
tools New features: 2021-02-22 13:59:43 -08:00
usr arch: ia64: Remove rest of perfmon support 2021-01-22 12:12:20 +05:30
virt KVM/arm64 fixes for 5.11, take #2 2021-02-12 14:07:39 +00:00
.clang-format clang-format: Update with the latest for_each macro list 2021-01-29 15:00:23 +01:00
.cocciconfig
.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 kbuild: Add support to build overlays (%.dtbo) 2021-02-04 09:00:04 -06:00
.mailmap Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-02-21 17:23:56 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: dccp: move Gerrit Renker to CREDITS 2021-01-14 10:53:49 -08:00
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 IOMMU Updates for Linux v5.12 2021-02-22 10:31:29 -08:00
Makefile Devicetree updates for v5.12: 2021-02-22 10:05:12 -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.