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Kan Liang 8d7f85e323 perf jevents: Don't stop at the first matched pmu when searching a events table 
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>
History 2024-10-02 14:58:03 -07:00
arch ARM fix for v6.11 2024-09-04 09:17:33 -07:00
block block: fix detection of unsupported WRITE SAME in blkdev_issue_write_zeroes 2024-08-28 08:49:25 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation Including fixes from can, bluetooth and wireless. 2024-09-05 17:08:01 -07:00
drivers Including fixes from can, bluetooth and wireless. 2024-09-05 17:08:01 -07:00
fs Tracing fixes for 6.11: 2024-09-05 16:29:41 -07:00
include Including fixes from can, bluetooth and wireless. 2024-09-05 17:08:01 -07:00
init Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
io_uring io_uring/kbuf: return correct iovec count from classic buffer peek 2024-08-30 10:45:54 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel bpf-6.11-rc7 2024-09-05 20:10:53 -07:00
lib linux_kselftest-kunit-fixes-6.11-rc7 2024-09-05 09:43:38 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm vfs-6.11-rc7.fixes 2024-09-04 09:33:57 -07:00
net ila: call nf_unregister_net_hooks() sooner 2024-09-05 14:57:12 -07:00
rust rust: macros: provide correct provenance when constructing THIS_MODULE 2024-09-02 09:14:28 +02:00
samples treewide: remove unnecessary <linux/version.h> inclusion 2024-08-12 18:36:44 +09:00
scripts scripts: fix gfp-translate after ___GFP_*_BITS conversion to an enum 2024-09-01 17:59:01 -07:00
security Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging 2024-09-01 09:18:48 +12:00
sound sound fixes for 6.11-rc6 2024-08-28 06:24:22 +12:00
tools perf jevents: Don't stop at the first matched pmu when searching a events table 2024-10-02 14:58:03 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) 2024-08-14 12:28:24 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.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: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap Rust fixes for v6.11 (2nd) 2024-09-05 16:35:57 -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 tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -07:00
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 Including fixes from can, bluetooth and wireless. 2024-09-05 17:08:01 -07:00
Makefile Rust fixes for v6.11 (2nd) 2024-09-05 16:35:57 -07:00
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.