Go to file
Linus Torvalds 9d64bf433c perf tools improvements and fixes for v6.8:
- Add Namhyung Kim as tools/perf/ co-maintainer, we're taking turns processing
   patches, switching roles from perf-tools to perf-tools-next at each Linux
   release.
 
 Data profiling:
 
 - Associate samples that identify loads and stores with data structures. This
   uses events available on Intel, AMD and others and DWARF info:
 
     # To get memory access samples in kernel for 1 second (on Intel)
     $ perf mem record -a -K --ldlat=4 -- sleep 1
 
     # Similar for the AMD (but it requires 6.3+ kernel for BPF filters)
     $ perf mem record -a --filter 'mem_op == load || mem_op == store, ip > 0x8000000000000000' -- sleep 1
 
   Then, amongst several modes of post processing, one can do things like:
 
     $ perf report -s type,typeoff --hierarchy --group --stdio
     ...
     #
     # Samples: 10K of events 'cpu/mem-loads,ldlat=4/P, cpu/mem-stores/P, dummy:u'
     # Event count (approx.): 602758064
     #
     #                    Overhead  Data Type / Data Type Offset
     # ...........................  ............................
     #
         26.09%   3.28%   0.00%     long unsigned int
            26.09%   3.28%   0.00%     long unsigned int +0 (no field)
         18.48%   0.73%   0.00%     struct page
            10.83%   0.02%   0.00%     struct page +8 (lru.next)
             3.90%   0.28%   0.00%     struct page +0 (flags)
             3.45%   0.06%   0.00%     struct page +24 (mapping)
             0.25%   0.28%   0.00%     struct page +48 (_mapcount.counter)
             0.02%   0.06%   0.00%     struct page +32 (index)
             0.02%   0.00%   0.00%     struct page +52 (_refcount.counter)
             0.02%   0.01%   0.00%     struct page +56 (memcg_data)
             0.00%   0.01%   0.00%     struct page +16 (lru.prev)
         15.37%  17.54%   0.00%     (stack operation)
            15.37%  17.54%   0.00%     (stack operation) +0 (no field)
         11.71%  50.27%   0.00%     (unknown)
            11.71%  50.27%   0.00%     (unknown) +0 (no field)
 
     $ perf annotate --data-type
     ...
     Annotate type: 'struct cfs_rq' in [kernel.kallsyms] (13 samples):
     ============================================================================
         samples     offset       size  field
              13          0        640  struct cfs_rq         {
               2          0         16      struct load_weight       load {
               2          0          8          unsigned long        weight;
               0          8          4          u32  inv_weight;
                                            };
               0         16          8      unsigned long    runnable_weight;
               0         24          4      unsigned int     nr_running;
               1         28          4      unsigned int     h_nr_running;
     ...
 
     $ perf annotate --data-type=page --group
     Annotate type: 'struct page' in [kernel.kallsyms] (480 samples):
      event[0] = cpu/mem-loads,ldlat=4/P
      event[1] = cpu/mem-stores/P
      event[2] = dummy:u
     ===================================================================================
              samples  offset  size  field
     447  33        0       0    64  struct page     {
     108   8        0       0     8	 long unsigned int  flags;
     319  13        0       8    40	 union       {
     319  13        0       8    40          struct          {
     236   2        0       8    16              union       {
     236   2        0       8    16                  struct list_head       lru {
     236   1        0       8     8                      struct list_head*  next;
       0   1        0      16     8                      struct list_head*  prev;
                                                     };
     236   2        0       8    16                  struct          {
     236   1        0       8     8                      void*      __filler;
       0   1        0      16     4                      unsigned int       mlock_count;
                                                     };
     236   2        0       8    16                  struct list_head       buddy_list {
     236   1        0       8     8                      struct list_head*  next;
       0   1        0      16     8                      struct list_head*  prev;
                                                     };
     236   2        0       8    16                  struct list_head       pcp_list {
     236   1        0       8     8                      struct list_head*  next;
       0   1        0      16     8                      struct list_head*  prev;
                                                     };
                                                 };
      82   4        0      24     8              struct address_space*      mapping;
       1   7        0      32     8              union       {
       1   7        0      32     8                  long unsigned int      index;
       1   7        0      32     8                  long unsigned int      share;
                                                 };
       0   0        0      40     8              long unsigned int  private;
                                                               };
 
   This uses the existing annotate code, calling objdump to do the disassembly,
   with improvements to avoid having this take too long, but longer term a
   switch to a disassembler library, possibly reusing code in the kernel will
   be pursued.
 
   This is the initial implementation, please use it and report impressions and
   bugs. Make sure the kernel-debuginfo packages match the running kernel. The
   'perf report' phase for non short perf.data files may take a while.
 
   There is a great article about it on LWN:
 
   https://lwn.net/Articles/955709/ - "Data-type profiling for perf"
 
   One last test I did while writing this text, on a AMD Ryzen 5950X, using a distro
   kernel, while doing a simple 'find /' on an otherwise idle system resulted in:
 
   # uname -r
   6.6.9-100.fc38.x86_64
   # perf -vv | grep BPF_
                    bpf: [ on  ]  # HAVE_LIBBPF_SUPPORT
          bpf_skeletons: [ on  ]  # HAVE_BPF_SKEL
   # rpm -qa | grep kernel-debuginfo
   kernel-debuginfo-common-x86_64-6.6.9-100.fc38.x86_64
   kernel-debuginfo-6.6.9-100.fc38.x86_64
   #
   # perf mem record -a --filter 'mem_op == load || mem_op == store, ip > 0x8000000000000000'
   ^C[ perf record: Woken up 1 times to write data ]
   [ perf record: Captured and wrote 2.199 MB perf.data (2913 samples) ]
   #
   # ls -la perf.data
   -rw-------. 1 root root 2346486 Jan  9 18:36 perf.data
   # perf evlist
   ibs_op//
   dummy:u
   # perf evlist -v
   ibs_op//: type: 11, size: 136, config: 0, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ADDR|CPU|PERIOD|IDENTIFIER|DATA_SRC|WEIGHT, read_format: ID, disabled: 1, inherit: 1, freq: 1, sample_id_all: 1
   dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 136, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|ADDR|CPU|IDENTIFIER|DATA_SRC|WEIGHT, read_format: ID, inherit: 1, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, mmap_data: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
   #
   # perf report -s type,typeoff --hierarchy --group --stdio
   # Total Lost Samples: 0
   #
   # Samples: 2K of events 'ibs_op//, dummy:u'
   # Event count (approx.): 1904553038
   #
   #            Overhead  Data Type / Data Type Offset
   # ...................  ............................
   #
       73.70%   0.00%     (unknown)
          73.70%   0.00%     (unknown) +0 (no field)
        3.01%   0.00%     long unsigned int
           3.00%   0.00%     long unsigned int +0 (no field)
           0.01%   0.00%     long unsigned int +2 (no field)
        2.73%   0.00%     struct task_struct
           1.71%   0.00%     struct task_struct +52 (on_cpu)
           0.38%   0.00%     struct task_struct +2104 (rcu_read_unlock_special.b.blocked)
           0.23%   0.00%     struct task_struct +2100 (rcu_read_lock_nesting)
           0.14%   0.00%     struct task_struct +2384 ()
           0.06%   0.00%     struct task_struct +3096 (signal)
           0.05%   0.00%     struct task_struct +3616 (cgroups)
           0.05%   0.00%     struct task_struct +2344 (active_mm)
           0.02%   0.00%     struct task_struct +46 (flags)
           0.02%   0.00%     struct task_struct +2096 (migration_disabled)
           0.01%   0.00%     struct task_struct +24 (__state)
           0.01%   0.00%     struct task_struct +3956 (mm_cid_active)
           0.01%   0.00%     struct task_struct +1048 (cpus_ptr)
           0.01%   0.00%     struct task_struct +184 (se.group_node.next)
           0.01%   0.00%     struct task_struct +20 (thread_info.cpu)
           0.00%   0.00%     struct task_struct +104 (on_rq)
           0.00%   0.00%     struct task_struct +2456 (pid)
        1.36%   0.00%     struct module
           0.59%   0.00%     struct module +952 (kallsyms)
           0.42%   0.00%     struct module +0 (state)
           0.23%   0.00%     struct module +8 (list.next)
           0.12%   0.00%     struct module +216 (syms)
        0.95%   0.00%     struct inode
           0.41%   0.00%     struct inode +40 (i_sb)
           0.22%   0.00%     struct inode +0 (i_mode)
           0.06%   0.00%     struct inode +76 (i_rdev)
           0.06%   0.00%     struct inode +56 (i_security)
   <SNIP>
 
 perf top/report:
 
 - Don't ignore job control, allowing control+Z + bg to work.
 
 - Add s390 raw data interpretation for PAI (Processor Activity Instrumentation)
   counters.
 
 perf archive:
 
 - Add new option '--all' to pack perf.data with DSOs.
 
 - Add new option '--unpack' to expand tarballs.
 
 Initialization speedups:
 
 - Lazily initialize zstd streams to save memory when not using it.
 
 - Lazily allocate/size mmap event copy.
 
 - Lazy load kernel symbols in 'perf record'.
 
 - Be lazier in allocating lost samples buffer in 'perf record'.
 
 - Don't synthesize BPF events when disabled via the command line (perf record --no-bpf-event).
 
 Assorted improvements:
 
 - Show note on AMD systems that the :p, :pp, :ppp and :P are all the same, as
   IBS (Instruction Based Sampling) is used and it is inherentely precise, not
   having levels of precision like in Intel systems.
 
 - When 'cycles' isn't available, fall back to the "task-clock" event when not
   system wide, not to 'cpu-clock'.
 
 - Add --debug-file option to redirect debug output, e.g.:
 
     $ perf --debug-file /tmp/perf.log record -v true
 
 - Shrink 'struct map' to under one cacheline by avoiding function pointers for
   selecting if addresses are identity or DSO relative, and using just a byte for
   some boolean struct members.
 
 - Resolve the arch specific strerrno just once to use in perf_env__arch_strerrno().
 
 - Reduce memory for recording PERF_RECORD_LOST_SAMPLES event.
 
 Assorted fixes:
 
 - Fix the default 'perf top' usage on Intel hybrid systems, now it starts with
   a browser showing the number of samples for Efficiency (cpu_atom/cycles/P) and
   Performance (cpu_core/cycles/P). This behaviour is similar on ARM64, with its
   respective set of big.LITTLE processors.
 
 - Fix segfault on build_mem_topology() error path.
 
 - Fix 'perf mem' error on hybrid related to availability of mem event in a PMU.
 
 - Fix missing reference count gets (map, maps) in the db-export code.
 
 - Avoid recursively taking env->bpf_progs.lock in the 'perf_env' code.
 
 - Use the newly introduced maps__for_each_map() to add missing locking around
   iteration of 'struct map' entries.
 
 - Parse NOTE segments until the build id is found, don't stop on the first one,
   ELF files may have several such NOTE segments.
 
 - Remove 'egrep' usage, its deprecated, use 'grep -E' instead.
 
 - Warn first about missing libelf, not libbpf, that depends on libelf.
 
 - Use alternative to 'find ... -printf' as this isn't supported in busybox.
 
 - Address python 3.6 DeprecationWarning for string scapes.
 
 - Fix memory leak in uniq() in libsubcmd.
 
 - Fix man page formatting for 'perf lock'
 
 - Fix some spelling mistakes.
 
 perf tests:
 
 - Fail shell tests that needs some symbol in perf itself if it is stripped.
   These tests check if a symbol is resolved, if some hot function is indeed
   detected by profiling, etc.
 
 - The 'perf test sigtrap' test is currently failing on PREEMPT_RT, skip it if
   sleeping spinlocks are detected (using BTF) and point to the mailing list
   discussion about it. This test is also being skipped on several architectures
   (powerpc, s390x, arm and aarch64) due to other pending issues with intruction
   breakpoints.
 
 - Adjust test case perf record offcpu profiling tests for s390.
 
 - Fix 'Setup struct perf_event_attr' fails on s390 on z/VM guest, addressing
   issues caused by the fallback from cycles to task-clock done in this release.
 
 - Fix mask for VG register in the user-regs test.
 
 - Use shellcheck on 'perf test' shell scripts automatically to make sure changes
   don't introduce things it flags as problematic.
 
 - Add option to change objdump binary and allow it to be set via 'perf config'.
 
 - Add basic 'perf script', 'perf list --json" and 'perf diff' tests.
 
 - Basic branch counter support.
 
 - Make DSO tests a suite rather than individual.
 
 - Remove atomics from test_loop to avoid test failures.
 
 - Fix call chain match on powerpc for the record+probe_libc_inet_pton test.
 
 - Improve Intel hybrid tests.
 
 Vendor event files (JSON):
 
 powerpc:
 
 - Update datasource event name to fix duplicate events on IBM's Power10.
 
 - Add PVN for HX-C2000 CPU with Power8 Architecture.
 
 Intel:
 
 - Alderlake/rocketlake metric fixes.
 
 - Update emeraldrapids events to v1.02.
 
 - Update icelakex events to v1.23.
 
 - Update sapphirerapids events to v1.17.
 
 - Add skx, clx, icx and spr upi bandwidth metric.
 
 AMD:
 
 - Add Zen 4 memory controller events.
 
 RISC-V:
 
 - Add StarFive Dubhe-80 and Dubhe-90 JSON files.
   https://www.starfivetech.com/en/site/cpu-u
 
 - Add T-HEAD C9xx JSON file.
   https://github.com/riscv-software-src/opensbi/blob/master/docs/platform/thead-c9xx.md
 
 ARM64:
 
 - Remove UTF-8 characters from cmn.json, that were causing build failure in some
   distros.
 
 - Add core PMU events and metrics for Ampere One X.
 
 - Rename Ampere One's BPU_FLUSH_MEM_FAULT to GPC_FLUSH_MEM_FAULT
 
 libperf:
 
 - Rename several perf_cpu_map constructor names to clarify what they really do.
 
 - Ditto for some other methods, coping with some issues in their semantics,
   like perf_cpu_map__empty() -> perf_cpu_map__has_any_cpu_or_is_empty().
 
 - Document perf_cpu_map__nr()'s behavior
 
 perf stat:
 
 - Exit if parse groups fails.
 
 - Combine the -A/--no-aggr and --no-merge options.
 
 - Fix help message for --metric-no-threshold option.
 
 Hardware tracing:
 
 ARM64 CoreSight:
 
 - Bump minimum OpenCSD version to ensure a bugfix is present.
 
 - Add 'T' itrace option for timestamp trace
 
 - Set start vm addr of exectable file to 0 and don't ignore first sample on the
   arm-cs-trace-disasm.py 'perf script'.
 
 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQR2GiIUctdOfX2qHhGyPKLppCJ+JwUCZZ3FpgAKCRCyPKLppCJ+
 Jz21AQDB93J4X05bwHJlRloN3KuA3LuwzvAQkwFoJSfFFMDnzgEAgbAMF1sANirP
 5UcGxVgqoXWdrp9pkMcGlcFc7jsz5gA=
 =SM26
 -----END PGP SIGNATURE-----

Merge tag 'perf-tools-for-v6.8-1-2024-01-09' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

Pull perf tools updates from Arnaldo Carvalho de Melo:
 "Add Namhyung Kim as tools/perf/ co-maintainer, we're taking turns
  processing patches, switching roles from perf-tools to perf-tools-next
  at each Linux release.

  Data profiling:

   - Associate samples that identify loads and stores with data
     structures. This uses events available on Intel, AMD and others and
     DWARF info:

       # To get memory access samples in kernel for 1 second (on Intel)
       $ perf mem record -a -K --ldlat=4 -- sleep 1

       # Similar for the AMD (but it requires 6.3+ kernel for BPF filters)
       $ perf mem record -a --filter 'mem_op == load || mem_op == store, ip > 0x8000000000000000' -- sleep 1

     Then, amongst several modes of post processing, one can do things like:

       $ perf report -s type,typeoff --hierarchy --group --stdio
       ...
       #
       # Samples: 10K of events 'cpu/mem-loads,ldlat=4/P, cpu/mem-stores/P, dummy:u'
       # Event count (approx.): 602758064
       #
       #                    Overhead  Data Type / Data Type Offset
       # ...........................  ............................
       #
           26.09%   3.28%   0.00%     long unsigned int
              26.09%   3.28%   0.00%     long unsigned int +0 (no field)
           18.48%   0.73%   0.00%     struct page
              10.83%   0.02%   0.00%     struct page +8 (lru.next)
               3.90%   0.28%   0.00%     struct page +0 (flags)
               3.45%   0.06%   0.00%     struct page +24 (mapping)
               0.25%   0.28%   0.00%     struct page +48 (_mapcount.counter)
               0.02%   0.06%   0.00%     struct page +32 (index)
               0.02%   0.00%   0.00%     struct page +52 (_refcount.counter)
               0.02%   0.01%   0.00%     struct page +56 (memcg_data)
               0.00%   0.01%   0.00%     struct page +16 (lru.prev)
           15.37%  17.54%   0.00%     (stack operation)
              15.37%  17.54%   0.00%     (stack operation) +0 (no field)
           11.71%  50.27%   0.00%     (unknown)
              11.71%  50.27%   0.00%     (unknown) +0 (no field)

       $ perf annotate --data-type
       ...
       Annotate type: 'struct cfs_rq' in [kernel.kallsyms] (13 samples):
       ============================================================================
           samples     offset       size  field
                13          0        640  struct cfs_rq         {
                 2          0         16      struct load_weight       load {
                 2          0          8          unsigned long        weight;
                 0          8          4          u32  inv_weight;
                                              };
                 0         16          8      unsigned long    runnable_weight;
                 0         24          4      unsigned int     nr_running;
                 1         28          4      unsigned int     h_nr_running;
       ...

       $ perf annotate --data-type=page --group
       Annotate type: 'struct page' in [kernel.kallsyms] (480 samples):
        event[0] = cpu/mem-loads,ldlat=4/P
        event[1] = cpu/mem-stores/P
        event[2] = dummy:u
       ===================================================================================
                samples  offset  size  field
       447  33        0       0    64  struct page     {
       108   8        0       0     8	 long unsigned int  flags;
       319  13        0       8    40	 union       {
       319  13        0       8    40          struct          {
       236   2        0       8    16              union       {
       236   2        0       8    16                  struct list_head       lru {
       236   1        0       8     8                      struct list_head*  next;
         0   1        0      16     8                      struct list_head*  prev;
                                                       };
       236   2        0       8    16                  struct          {
       236   1        0       8     8                      void*      __filler;
         0   1        0      16     4                      unsigned int       mlock_count;
                                                       };
       236   2        0       8    16                  struct list_head       buddy_list {
       236   1        0       8     8                      struct list_head*  next;
         0   1        0      16     8                      struct list_head*  prev;
                                                       };
       236   2        0       8    16                  struct list_head       pcp_list {
       236   1        0       8     8                      struct list_head*  next;
         0   1        0      16     8                      struct list_head*  prev;
                                                       };
                                                   };
        82   4        0      24     8              struct address_space*      mapping;
         1   7        0      32     8              union       {
         1   7        0      32     8                  long unsigned int      index;
         1   7        0      32     8                  long unsigned int      share;
                                                   };
         0   0        0      40     8              long unsigned int  private;
                                                                 };

     This uses the existing annotate code, calling objdump to do the
     disassembly, with improvements to avoid having this take too long,
     but longer term a switch to a disassembler library, possibly
     reusing code in the kernel will be pursued.

     This is the initial implementation, please use it and report
     impressions and bugs. Make sure the kernel-debuginfo packages match
     the running kernel. The 'perf report' phase for non short perf.data
     files may take a while.

     There is a great article about it on LWN:

       https://lwn.net/Articles/955709/ - "Data-type profiling for perf"

     One last test I did while writing this text, on a AMD Ryzen 5950X,
     using a distro kernel, while doing a simple 'find /' on an
     otherwise idle system resulted in:

     # uname -r
     6.6.9-100.fc38.x86_64
     # perf -vv | grep BPF_
                      bpf: [ on  ]  # HAVE_LIBBPF_SUPPORT
            bpf_skeletons: [ on  ]  # HAVE_BPF_SKEL
     # rpm -qa | grep kernel-debuginfo
     kernel-debuginfo-common-x86_64-6.6.9-100.fc38.x86_64
     kernel-debuginfo-6.6.9-100.fc38.x86_64
     #
     # perf mem record -a --filter 'mem_op == load || mem_op == store, ip > 0x8000000000000000'
     ^C[ perf record: Woken up 1 times to write data ]
     [ perf record: Captured and wrote 2.199 MB perf.data (2913 samples) ]
     #
     # ls -la perf.data
     -rw-------. 1 root root 2346486 Jan  9 18:36 perf.data
     # perf evlist
     ibs_op//
     dummy:u
     # perf evlist -v
     ibs_op//: type: 11, size: 136, config: 0, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ADDR|CPU|PERIOD|IDENTIFIER|DATA_SRC|WEIGHT, read_format: ID, disabled: 1, inherit: 1, freq: 1, sample_id_all: 1
     dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 136, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|ADDR|CPU|IDENTIFIER|DATA_SRC|WEIGHT, read_format: ID, inherit: 1, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, mmap_data: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
     #
     # perf report -s type,typeoff --hierarchy --group --stdio
     # Total Lost Samples: 0
     #
     # Samples: 2K of events 'ibs_op//, dummy:u'
     # Event count (approx.): 1904553038
     #
     #            Overhead  Data Type / Data Type Offset
     # ...................  ............................
     #
         73.70%   0.00%     (unknown)
            73.70%   0.00%     (unknown) +0 (no field)
          3.01%   0.00%     long unsigned int
             3.00%   0.00%     long unsigned int +0 (no field)
             0.01%   0.00%     long unsigned int +2 (no field)
          2.73%   0.00%     struct task_struct
             1.71%   0.00%     struct task_struct +52 (on_cpu)
             0.38%   0.00%     struct task_struct +2104 (rcu_read_unlock_special.b.blocked)
             0.23%   0.00%     struct task_struct +2100 (rcu_read_lock_nesting)
             0.14%   0.00%     struct task_struct +2384 ()
             0.06%   0.00%     struct task_struct +3096 (signal)
             0.05%   0.00%     struct task_struct +3616 (cgroups)
             0.05%   0.00%     struct task_struct +2344 (active_mm)
             0.02%   0.00%     struct task_struct +46 (flags)
             0.02%   0.00%     struct task_struct +2096 (migration_disabled)
             0.01%   0.00%     struct task_struct +24 (__state)
             0.01%   0.00%     struct task_struct +3956 (mm_cid_active)
             0.01%   0.00%     struct task_struct +1048 (cpus_ptr)
             0.01%   0.00%     struct task_struct +184 (se.group_node.next)
             0.01%   0.00%     struct task_struct +20 (thread_info.cpu)
             0.00%   0.00%     struct task_struct +104 (on_rq)
             0.00%   0.00%     struct task_struct +2456 (pid)
          1.36%   0.00%     struct module
             0.59%   0.00%     struct module +952 (kallsyms)
             0.42%   0.00%     struct module +0 (state)
             0.23%   0.00%     struct module +8 (list.next)
             0.12%   0.00%     struct module +216 (syms)
          0.95%   0.00%     struct inode
             0.41%   0.00%     struct inode +40 (i_sb)
             0.22%   0.00%     struct inode +0 (i_mode)
             0.06%   0.00%     struct inode +76 (i_rdev)
             0.06%   0.00%     struct inode +56 (i_security)
     <SNIP>

  perf top/report:

   - Don't ignore job control, allowing control+Z + bg to work.

   - Add s390 raw data interpretation for PAI (Processor Activity
     Instrumentation) counters.

  perf archive:

   - Add new option '--all' to pack perf.data with DSOs.

   - Add new option '--unpack' to expand tarballs.

  Initialization speedups:

   - Lazily initialize zstd streams to save memory when not using it.

   - Lazily allocate/size mmap event copy.

   - Lazy load kernel symbols in 'perf record'.

   - Be lazier in allocating lost samples buffer in 'perf record'.

   - Don't synthesize BPF events when disabled via the command line
     (perf record --no-bpf-event).

  Assorted improvements:

   - Show note on AMD systems that the :p, :pp, :ppp and :P are all the
     same, as IBS (Instruction Based Sampling) is used and it is
     inherentely precise, not having levels of precision like in Intel
     systems.

   - When 'cycles' isn't available, fall back to the "task-clock" event
     when not system wide, not to 'cpu-clock'.

   - Add --debug-file option to redirect debug output, e.g.:

       $ perf --debug-file /tmp/perf.log record -v true

   - Shrink 'struct map' to under one cacheline by avoiding function
     pointers for selecting if addresses are identity or DSO relative,
     and using just a byte for some boolean struct members.

   - Resolve the arch specific strerrno just once to use in
     perf_env__arch_strerrno().

   - Reduce memory for recording PERF_RECORD_LOST_SAMPLES event.

  Assorted fixes:

   - Fix the default 'perf top' usage on Intel hybrid systems, now it
     starts with a browser showing the number of samples for Efficiency
     (cpu_atom/cycles/P) and Performance (cpu_core/cycles/P). This
     behaviour is similar on ARM64, with its respective set of
     big.LITTLE processors.

   - Fix segfault on build_mem_topology() error path.

   - Fix 'perf mem' error on hybrid related to availability of mem event
     in a PMU.

   - Fix missing reference count gets (map, maps) in the db-export code.

   - Avoid recursively taking env->bpf_progs.lock in the 'perf_env'
     code.

   - Use the newly introduced maps__for_each_map() to add missing
     locking around iteration of 'struct map' entries.

   - Parse NOTE segments until the build id is found, don't stop on the
     first one, ELF files may have several such NOTE segments.

   - Remove 'egrep' usage, its deprecated, use 'grep -E' instead.

   - Warn first about missing libelf, not libbpf, that depends on
     libelf.

   - Use alternative to 'find ... -printf' as this isn't supported in
     busybox.

   - Address python 3.6 DeprecationWarning for string scapes.

   - Fix memory leak in uniq() in libsubcmd.

   - Fix man page formatting for 'perf lock'

   - Fix some spelling mistakes.

  perf tests:

   - Fail shell tests that needs some symbol in perf itself if it is
     stripped. These tests check if a symbol is resolved, if some hot
     function is indeed detected by profiling, etc.

   - The 'perf test sigtrap' test is currently failing on PREEMPT_RT,
     skip it if sleeping spinlocks are detected (using BTF) and point to
     the mailing list discussion about it. This test is also being
     skipped on several architectures (powerpc, s390x, arm and aarch64)
     due to other pending issues with intruction breakpoints.

   - Adjust test case perf record offcpu profiling tests for s390.

   - Fix 'Setup struct perf_event_attr' fails on s390 on z/VM guest,
     addressing issues caused by the fallback from cycles to task-clock
     done in this release.

   - Fix mask for VG register in the user-regs test.

   - Use shellcheck on 'perf test' shell scripts automatically to make
     sure changes don't introduce things it flags as problematic.

   - Add option to change objdump binary and allow it to be set via
     'perf config'.

   - Add basic 'perf script', 'perf list --json" and 'perf diff' tests.

   - Basic branch counter support.

   - Make DSO tests a suite rather than individual.

   - Remove atomics from test_loop to avoid test failures.

   - Fix call chain match on powerpc for the record+probe_libc_inet_pton
     test.

   - Improve Intel hybrid tests.

  Vendor event files (JSON):

  powerpc:

   - Update datasource event name to fix duplicate events on IBM's
     Power10.

   - Add PVN for HX-C2000 CPU with Power8 Architecture.

  Intel:

   - Alderlake/rocketlake metric fixes.

   - Update emeraldrapids events to v1.02.

   - Update icelakex events to v1.23.

   - Update sapphirerapids events to v1.17.

   - Add skx, clx, icx and spr upi bandwidth metric.

  AMD:

   - Add Zen 4 memory controller events.

  RISC-V:

   - Add StarFive Dubhe-80 and Dubhe-90 JSON files.
       https://www.starfivetech.com/en/site/cpu-u

   - Add T-HEAD C9xx JSON file.
       https://github.com/riscv-software-src/opensbi/blob/master/docs/platform/thead-c9xx.md

  ARM64:

   - Remove UTF-8 characters from cmn.json, that were causing build
     failure in some distros.

   - Add core PMU events and metrics for Ampere One X.

   - Rename Ampere One's BPU_FLUSH_MEM_FAULT to GPC_FLUSH_MEM_FAULT

  libperf:

   - Rename several perf_cpu_map constructor names to clarify what they
     really do.

   - Ditto for some other methods, coping with some issues in their
     semantics, like perf_cpu_map__empty() ->
     perf_cpu_map__has_any_cpu_or_is_empty().

   - Document perf_cpu_map__nr()'s behavior

  perf stat:

   - Exit if parse groups fails.

   - Combine the -A/--no-aggr and --no-merge options.

   - Fix help message for --metric-no-threshold option.

  Hardware tracing:

  ARM64 CoreSight:

   - Bump minimum OpenCSD version to ensure a bugfix is present.

   - Add 'T' itrace option for timestamp trace

   - Set start vm addr of exectable file to 0 and don't ignore first
     sample on the arm-cs-trace-disasm.py 'perf script'"

* tag 'perf-tools-for-v6.8-1-2024-01-09' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits)
  MAINTAINERS: Add Namhyung as tools/perf/ co-maintainer
  perf test: test case 'Setup struct perf_event_attr' fails on s390 on z/vm
  perf db-export: Fix missing reference count get in call_path_from_sample()
  perf tests: Add perf script test
  libsubcmd: Fix memory leak in uniq()
  perf TUI: Don't ignore job control
  perf vendor events intel: Update sapphirerapids events to v1.17
  perf vendor events intel: Update icelakex events to v1.23
  perf vendor events intel: Update emeraldrapids events to v1.02
  perf vendor events intel: Alderlake/rocketlake metric fixes
  perf x86 test: Add hybrid test for conflicting legacy/sysfs event
  perf x86 test: Update hybrid expectations
  perf vendor events amd: Add Zen 4 memory controller events
  perf stat: Fix hard coded LL miss units
  perf record: Reduce memory for recording PERF_RECORD_LOST_SAMPLES event
  perf env: Avoid recursively taking env->bpf_progs.lock
  perf annotate: Add --insn-stat option for debugging
  perf annotate: Add --type-stat option for debugging
  perf annotate: Support event group display
  perf annotate: Add --data-type option
  ...
2024-01-19 14:25:23 -08:00
arch arm64 fixes for -rc1 2024-01-19 13:36:15 -08:00
block for-6.8/block-2024-01-18 2024-01-18 18:22:40 -08:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: scomp - fix req->dst buffer overflow 2023-12-29 11:25:56 +08:00
Documentation arm64 fixes for -rc1 2024-01-19 13:36:15 -08:00
drivers Devicetree updates for v6.8, part 2: 2024-01-19 13:00:45 -08:00
fs strlcpy removal for v6.8-rc1 2024-01-19 13:49:16 -08:00
include strlcpy removal for v6.8-rc1 2024-01-19 13:49:16 -08:00
init Driver core changes for 6.8-rc1 2024-01-18 09:48:40 -08:00
io_uring for-6.8/io_uring-2024-01-18 2024-01-18 18:17:57 -08:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel kgdb patches for 6.8 2024-01-18 17:53:22 -08:00
lib strlcpy removal for v6.8-rc1 2024-01-19 13:49:16 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
net Assorted CephFS fixes and cleanups with nothing standing out. 2024-01-19 09:58:55 -08:00
rust Rust changes for v6.8 2024-01-11 13:05:41 -08:00
samples tracing updates for 6.8: 2024-01-18 14:35:29 -08:00
scripts LoongArch changes for v6.8 2024-01-19 13:30:49 -08:00
security + Features 2024-01-19 10:53:55 -08:00
sound sound fixes for 6.8-rc1 2024-01-19 12:30:29 -08:00
tools perf tools improvements and fixes for v6.8: 2024-01-19 14:25:23 -08:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt Generic: 2024-01-17 13:03:37 -08:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.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 Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap Char/Misc and other Driver changes for 6.8-rc1 2024-01-17 16:47:17 -08:00
.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 Including fixes from bpf and netfilter. 2024-01-18 17:33:50 -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 perf tools improvements and fixes for v6.8: 2024-01-19 14:25:23 -08:00
Makefile Kbuild updates for v6.8 2024-01-18 17:57:07 -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.