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Kan Liang 9042456a80 perf jevents: Don't stop at the first matched pmu when searching a events table 
[ Upstream commit 8d7f85e323 ]

The "perf all PMU test" fails on a Coffee Lake machine.

The failure is caused by the below change in the commit e2641db83f
("perf vendor events: Add/update skylake events/metrics").

+    {
+        "BriefDescription": "This 48-bit fixed counter counts the UCLK cycles",
+        "Counter": "FIXED",
+        "EventCode": "0xff",
+        "EventName": "UNC_CLOCK.SOCKET",
+        "PerPkg": "1",
+        "PublicDescription": "This 48-bit fixed counter counts the UCLK cycles.",
+        "Unit": "cbox_0"
     }

The other cbox events have the unit name "CBOX", while the fixed counter
has a unit name "cbox_0". So the events_table will maintain separate
entries for cbox and cbox_0.

The perf_pmus__print_pmu_events() calculates the total number of events,
allocate an aliases buffer, store all the events into the buffer, sort,
and print all the aliases one by one.

The problem is that the calculated total number of events doesn't match
the stored events in the aliases buffer.

The perf_pmu__num_events() is used to calculate the number of events. It
invokes the pmu_events_table__num_events() to go through the entire
events_table to find all events. Because of the
pmu_uncore_alias_match(), the suffix of uncore PMU will be ignored. So
the events for cbox and cbox_0 are all counted.

When storing events into the aliases buffer, the
perf_pmu__for_each_event() only process the events for cbox.

Since a bigger buffer was allocated, the last entry are all 0.
When printing all the aliases, null will be outputted, and trigger the
failure.

The mismatch was introduced from the commit e3edd6cf63 ("perf
pmu-events: Reduce processed events by passing PMU"). The
pmu_events_table__for_each_event() stops immediately once a pmu is set.
But for uncore, especially this case, the method is wrong and mismatch
what perf does in the perf_pmu__num_events().

With the patch,
$ perf list pmu | grep -A 1 clock.socket
   unc_clock.socket
        [This 48-bit fixed counter counts the UCLK cycles. Unit: uncore_cbox_0
$ perf test "perf all PMU test"
  107: perf all PMU test                                               : Ok

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/all/202407101021.2c8baddb-oliver.sang@intel.com/
Fixes: e3edd6cf63 ("perf pmu-events: Reduce processed events by passing PMU")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Benjamin Gray <bgray@linux.ibm.com>
Cc: Xu Yang <xu.yang_2@nxp.com>
Cc: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241001021431.814811-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-12-05 14:02:18 +01:00
arch x86: fix off-by-one in access_ok() 2024-12-05 14:02:17 +01:00
block block: fix bio_split_rw_at to take zone_write_granularity into account 2024-12-05 14:01:14 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-05 14:01:18 +01:00
Documentation dt-bindings: PCI: mediatek-gen3: Allow exact number of clocks only 2024-12-05 14:02:18 +01:00
drivers PCI: Fix reset_method_store() memory leak 2024-12-05 14:02:18 +01:00
fs gfs2: Fix unlinked inode cleanup 2024-12-05 14:02:18 +01:00
include kunit: skb: use "gfp" variable instead of hardcoding GFP_KERNEL 2024-12-05 14:02:13 +01:00
init initramfs: avoid filename buffer overrun 2024-12-05 14:01:12 +01:00
io_uring io_uring/rw: fix missing NOWAIT check for O_DIRECT start write 2024-10-31 08:21:02 -06:00
ipc struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
kernel trace/trace_event_perf: remove duplicate samples on the first tracepoint event 2024-12-05 14:02:02 +01:00
lib kasan: move checks to do_strncpy_from_user 2024-12-05 14:02:12 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/mmap: fix __mmap_region() error handling in rare merge failure case 2024-11-22 15:30:26 +01:00
net bpf: fix recursive lock when verdict program return SK_PASS 2024-12-05 14:02:01 +01:00
rust rust: helpers: Avoid raw_spin_lock initialization for PREEMPT_RT 2024-12-05 14:01:23 +01:00
samples bpf: Fix the xdp_adjust_tail sample prog issue 2024-12-05 14:01:42 +01:00
scripts checkpatch: always parse orig_commit in fixes tag 2024-12-05 14:02:09 +01:00
security integrity-v6.12 2024-11-12 13:06:31 -08:00
sound ALSA: 6fire: Release resources at card release 2024-12-05 14:01:58 +01:00
tools perf jevents: Don't stop at the first matched pmu when searching a events table 2024-12-05 14:02:18 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt ARM64: 2024-10-21 11:22:04 -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 scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -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 MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -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 MAINTAINERS: appoint myself the XFS maintainer for 6.12 LTS 2024-12-05 14:01:10 +01:00
Makefile Linux 6.12.1 2024-11-22 15:30:26 +01:00
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.