tjh.dev/kernel at v6.4-rc2

Pull perf tool updates from Arnaldo Carvalho de Melo:
"Third version of perf tool updates, with the build problems with with
using a 'vmlinux.h' generated from the main build fixed, and the bpf
skeleton build disabled by default.

Build:

- Require libtraceevent to build, one can disable it using
NO_LIBTRACEEVENT=1.

It is required for tools like 'perf sched', 'perf kvm', 'perf
trace', etc.

libtraceevent is available in most distros so installing
'libtraceevent-devel' should be a one-time event to continue
building perf as usual.

Using NO_LIBTRACEEVENT=1 produces tooling that is functional and
sufficient for lots of users not interested in those libtraceevent
dependent features.

- Allow Python support in 'perf script' when libtraceevent isn't
linked, as not all features requires it, for instance Intel PT does
not use tracepoints.

- Error if the python interpreter needed for jevents to work isn't
available and NO_JEVENTS=1 isn't set, preventing a build without
support for JSON vendor events, which is a rare but possible
condition. The two check error messages:

$(error ERROR: No python interpreter needed for jevents generation. Install python or build with NO_JEVENTS=1.)
$(error ERROR: Python interpreter needed for jevents generation too old (older than 3.6). Install a newer python or build with NO_JEVENTS=1.)

- Make libbpf 1.0 the minimum required when building with out of
tree, distro provided libbpf.

- Use libsdtc++'s and LLVM's libcxx's __cxa_demangle, a portable C++
demangler, add 'perf test' entry for it.

- Make binutils libraries opt in, as distros disable building with it
due to licensing, they were used for C++ demangling, for instance.

- Switch libpfm4 to opt-out rather than opt-in, if libpfm-devel (or
equivalent) isn't installed, we'll just have a build warning:

Makefile.config:1144: libpfm4 not found, disables libpfm4 support. Please install libpfm4-dev

- Add a feature test for scandirat(), that is not implemented so far
in musl and uclibc, disabling features that need it, such as
scanning for tracepoints in /sys/kernel/tracing/events.

perf BPF filters:

- New feature where BPF can be used to filter samples, for instance:

$ sudo ./perf record -e cycles --filter 'period > 1000' true
$ sudo ./perf script
perf-exec 2273949 546850.708501: 5029 cycles: ffffffff826f9e25 finish_wait+0x5 ([kernel.kallsyms])
perf-exec 2273949 546850.708508: 32409 cycles: ffffffff826f9e25 finish_wait+0x5 ([kernel.kallsyms])
perf-exec 2273949 546850.708526: 143369 cycles: ffffffff82b4cdbf xas_start+0x5f ([kernel.kallsyms])
perf-exec 2273949 546850.708600: 372650 cycles: ffffffff8286b8f7 __pagevec_lru_add+0x117 ([kernel.kallsyms])
perf-exec 2273949 546850.708791: 482953 cycles: ffffffff829190de __mod_memcg_lruvec_state+0x4e ([kernel.kallsyms])
true 2273949 546850.709036: 501985 cycles: ffffffff828add7c tlb_gather_mmu+0x4c ([kernel.kallsyms])
true 2273949 546850.709292: 503065 cycles: 7f2446d97c03 _dl_map_object_deps+0x973 (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)

- In addition to 'period' (PERF_SAMPLE_PERIOD), the other
PERF_SAMPLE_ can be used for filtering, and also some other sample
accessible values, from tools/perf/Documentation/perf-record.txt:

Essentially the BPF filter expression is:

<term> <operator> <value> (("," | "||") <term> <operator> <value>)*

The <term> can be one of:
ip, id, tid, pid, cpu, time, addr, period, txn, weight, phys_addr,
code_pgsz, data_pgsz, weight1, weight2, weight3, ins_lat, retire_lat,
p_stage_cyc, mem_op, mem_lvl, mem_snoop, mem_remote, mem_lock,
mem_dtlb, mem_blk, mem_hops

The <operator> can be one of:
==, !=, >, >=, <, <=, &

The <value> can be one of:
<number> (for any term)
na, load, store, pfetch, exec (for mem_op)
l1, l2, l3, l4, cxl, io, any_cache, lfb, ram, pmem (for mem_lvl)
na, none, hit, miss, hitm, fwd, peer (for mem_snoop)
remote (for mem_remote)
na, locked (for mem_locked)
na, l1_hit, l1_miss, l2_hit, l2_miss, any_hit, any_miss, walk, fault (for mem_dtlb)
na, by_data, by_addr (for mem_blk)
hops0, hops1, hops2, hops3 (for mem_hops)

perf lock contention:

- Show lock type with address.

- Track and show mmap_lock, siglock and per-cpu rq_lock with address.
This is done for mmap_lock by following the current->mm pointer:

$ sudo ./perf lock con -abl -- sleep 10
contended total wait max wait avg wait address symbol
...
16344 312.30 ms 2.22 ms 19.11 us ffff8cc702595640
17686 310.08 ms 1.49 ms 17.53 us ffff8cc7025952c0
3 84.14 ms 45.79 ms 28.05 ms ffff8cc78114c478 mmap_lock
3557 76.80 ms 68.75 us 21.59 us ffff8cc77ca3af58
1 68.27 ms 68.27 ms 68.27 ms ffff8cda745dfd70
9 54.53 ms 7.96 ms 6.06 ms ffff8cc7642a48b8 mmap_lock
14629 44.01 ms 60.00 us 3.01 us ffff8cc7625f9ca0
3481 42.63 ms 140.71 us 12.24 us ffffffff937906ac vmap_area_lock
16194 38.73 ms 42.15 us 2.39 us ffff8cd397cbc560
11 38.44 ms 10.39 ms 3.49 ms ffff8ccd6d12fbb8 mmap_lock
1 5.43 ms 5.43 ms 5.43 ms ffff8cd70018f0d8
1674 5.38 ms 422.93 us 3.21 us ffffffff92e06080 tasklist_lock
581 4.51 ms 130.68 us 7.75 us ffff8cc9b1259058
5 3.52 ms 1.27 ms 703.23 us ffff8cc754510070
112 3.47 ms 56.47 us 31.02 us ffff8ccee38b3120
381 3.31 ms 73.44 us 8.69 us ffffffff93790690 purge_vmap_area_lock
255 3.19 ms 36.35 us 12.49 us ffff8d053ce30c80

- Update default map size to 16384.

- Allocate single letter option -M for --map-nr-entries, as it is
proving being frequently used.

- Fix struct rq lock access for older kernels with BPF's CO-RE
(Compile once, run everywhere).

- Fix problems found with MSAn.

perf report/top:

- Add inline information when using --call-graph=fp or lbr, as was
already done to the --call-graph=dwarf callchain mode.

- Improve the 'srcfile' sort key performance by really using an
optimization introduced in 6.2 for the 'srcline' sort key that
avoids calling addr2line for comparision with each sample.

perf sched:

- Make 'perf sched latency/map/replay' to use "sched:sched_waking"
instead of "sched:sched_waking", consistent with 'perf record'
since d566a9c2d482 ("perf sched: Prefer sched_waking event when it
exists").

perf ftrace:

- Make system wide the default target for latency subcommand, run the
following command then generate some network traffic and press
control+C:

# perf ftrace latency -T __kfree_skb
^C
DURATION | COUNT | GRAPH |
0 - 1 us | 27 | ############# |
1 - 2 us | 22 | ########### |
2 - 4 us | 8 | #### |
4 - 8 us | 5 | ## |
8 - 16 us | 24 | ############ |
16 - 32 us | 2 | # |
32 - 64 us | 1 | |
64 - 128 us | 0 | |
128 - 256 us | 0 | |
256 - 512 us | 0 | |
512 - 1024 us | 0 | |
1 - 2 ms | 0 | |
2 - 4 ms | 0 | |
4 - 8 ms | 0 | |
8 - 16 ms | 0 | |
16 - 32 ms | 0 | |
32 - 64 ms | 0 | |
64 - 128 ms | 0 | |
128 - 256 ms | 0 | |
256 - 512 ms | 0 | |
512 - 1024 ms | 0 | |
1 - ... s | 0 | |
#

perf top:

- Add --branch-history (LBR: Last Branch Record) option, just like
already available for 'perf record'.

- Fix segfault in thread__comm_len() where thread->comm was being
used outside thread->comm_lock.

perf annotate:

- Allow configuring objdump and addr2line in ~/.perfconfig., so that
you can use alternative binaries, such as llvm's.

perf kvm:

- Add TUI mode for 'perf kvm stat report'.

Reference counting:

- Add reference count checking infrastructure to check for use after
free, done to the 'cpumap', 'namespaces', 'maps' and 'map' structs,
more to come.

To build with it use -DREFCNT_CHECKING=1 in the make command line
to build tools/perf. Documented at:

https://perf.wiki.kernel.org/index.php/Reference_Count_Checking

- The above caught, for instance, fix, present in this series:

- Fix maps use after put in 'perf test "Share thread maps"':

'maps' is copied from leader, but the leader is put on line 79
and then 'maps' is used to read the reference count below - so
a use after put, with the put of maps happening within
thread__put.

Fixed by reversing the order of puts so that the leader is put
last.

- Also several fixes were made to places where reference counts were
not being held.

- Make this one of the tests in 'make -C tools/perf build-test' to
regularly build test it and to make sure no direct access to the
reference counted structs are made, doing that via accessors to
check the validity of the struct pointer.

ARM64:

- Fix 'perf report' segfault when filtering coresight traces by
sparse lists of CPUs.

- Add support for 'simd' as a sort field for 'perf report', to show
ARM's NEON SIMD's predicate flags: "partial" and "empty".

arm64 vendor events:

- Add N1 metrics.

Intel vendor events:

- Add graniterapids, grandridge and sierraforrest events.

- Refresh events for: alderlake, aldernaken, broadwell, broadwellde,
broadwellx, cascadelakx, haswell, haswellx, icelake, icelakex,
jaketown, meteorlake, knightslanding, sandybridge, sapphirerapids,
silvermont, skylake, tigerlake and westmereep-dp

- Refresh metrics for alderlake-n, broadwell, broadwellde,
broadwellx, haswell, haswellx, icelakex, ivybridge, ivytown and
skylakex.

perf stat:

- Implement --topdown using JSON metrics.

- Add TopdownL1 JSON metric as a default if present, but disable it
for now for some Intel hybrid architectures, a series of patches
addressing this is being reviewed and will be submitted for v6.5.

- Use metrics for --smi-cost.

- Update topdown documentation.

Vendor events (JSON) infrastructure:

- Add support for computing and printing metric threshold values. For
instance, here is one found in thesapphirerapids json file:

{
"BriefDescription": "Percentage of cycles spent in System Management Interrupts.",
"MetricExpr": "((msr@aperf@ - cycles) / msr@aperf@ if msr@smi@ > 0 else 0)",
"MetricGroup": "smi",
"MetricName": "smi_cycles",
"MetricThreshold": "smi_cycles > 0.1",
"ScaleUnit": "100%"
},

- Test parsing metric thresholds with the fake PMU in 'perf test
pmu-events'.

- Support for printing metric thresholds in 'perf list'.

- Add --metric-no-threshold option to 'perf stat'.

- Add rand (reverse and) and has_pmem (optane memory) support to
metrics.

- Sort list of input files to avoid depending on the order from
readdir() helping in obtaining reproducible builds.

S/390:

- Add common metrics: - CPI (cycles per instruction), prbstate (ratio
of instructions executed in problem state compared to total number
of instructions), l1mp (Level one instruction and data cache misses
per 100 instructions).

- Add cache metrics for z13, z14, z15 and z16.

- Add metric for TLB and cache.

ARM:

- Add raw decoding for SPE (Statistical Profiling Extension) v1.3 MTE
(Memory Tagging Extension) and MOPS (Memory Operations) load/store.

Intel PT hardware tracing:

- Add event type names UINTR (User interrupt delivered) and UIRET
(Exiting from user interrupt routine), documented in table 32-50
"CFE Packet Type and Vector Fields Details" in the Intel Processor
Trace chapter of The Intel SDM Volume 3 version 078.

- Add support for new branch instructions ERETS and ERETU.

- Fix CYC timestamps after standalone CBR

ARM CoreSight hardware tracing:

- Allow user to override timestamp and contextid settings.

- Fix segfault in dso lookup.

- Fix timeless decode mode detection.

- Add separate decode paths for timeless and per-thread modes.

auxtrace:

- Fix address filter entire kernel size.

Miscellaneous:

- Fix use-after-free and unaligned bugs in the PLT handling routines.

- Use zfree() to reduce chances of use after free.

- Add missing 0x prefix for addresses printed in hexadecimal in 'perf
probe'.

- Suppress massive unsupported target platform errors in the unwind
code.

- Fix return incorrect build_id size in elf_read_build_id().

- Fix 'perf scripts intel-pt-events.py' IPC output for Python 2 .

- Add missing new parameter in kfree_skb tracepoint to the python
scripts using it.

- Add 'perf bench syscall fork' benchmark.

- Add support for printing PERF_MEM_LVLNUM_UNC (Uncached access) in
'perf mem'.

- Fix wrong size expectation for perf test 'Setup struct
perf_event_attr' caused by the patch adding
perf_event_attr::config3.

- Fix some spelling mistakes"

* tag 'perf-tools-for-v6.4-3-2023-05-06' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (365 commits)
Revert "perf build: Make BUILD_BPF_SKEL default, rename to NO_BPF_SKEL"
Revert "perf build: Warn for BPF skeletons if endian mismatches"
perf metrics: Fix SEGV with --for-each-cgroup
perf bpf skels: Stop using vmlinux.h generated from BTF, use subset of used structs + CO-RE
perf stat: Separate bperf from bpf_profiler
perf test record+probe_libc_inet_pton: Fix call chain match on x86_64
perf test record+probe_libc_inet_pton: Fix call chain match on s390
perf tracepoint: Fix memory leak in is_valid_tracepoint()
perf cs-etm: Add fix for coresight trace for any range of CPUs
perf build: Fix unescaped # in perf build-test
perf unwind: Suppress massive unsupported target platform errors
perf script: Add new parameter in kfree_skb tracepoint to the python scripts using it
perf script: Print raw ip instead of binary offset for callchain
perf symbols: Fix return incorrect build_id size in elf_read_build_id()
perf list: Modify the warning message about scandirat(3)
perf list: Fix memory leaks in print_tracepoint_events()
perf lock contention: Rework offset calculation with BPF CO-RE
perf lock contention: Fix struct rq lock access
perf stat: Disable TopdownL1 on hybrid
perf stat: Avoid SEGV on counter->name
...

f085df1b

Linus Torvalds

2 years ago

Merge tag 'sched_urgent_for_v6.4_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

f3b9e8e4

Linus Torvalds

2 years ago

branches 2

master 12 hours ago default

compare

for-next 11 months ago

compare

tags 915

v6.19-rc5

12 hours ago latest

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 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.

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