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In some of the powerpc platforms, event group testcase fails as below: # perf test -v 'Event groups' 69: Event groups : --- start --- test child forked, pid 9765 Using CPUID 0x00820200 Using hv_24x7 for uncore pmu event 0x0 0x0, 0x0 0x0, 0x0 0x0: Fail 0x0 0x0, 0x0 0x0, 0x1 0x3: Pass The testcase creates various combinations of hw, sw and uncore PMU events and verify group creation succeeds or fails as expected. This tests one of the limitation in perf where it doesn't allow creating a group of events from different hw PMUs. The testcase starts a leader event and opens two sibling events. The combination the fails is three hardware events in a group. "0x0 0x0, 0x0 0x0, 0x0 0x0: Fail" Type zero and config zero which translates to PERF_TYPE_HARDWARE and PERF_COUNT_HW_CPU_CYCLE. There is event constraint in powerpc that events using same counter cannot be programmed in a group. Here there is one alternative event for cycles, hence one leader and only one sibling event can go in as a group. if all three events (leader and two sibling events), are hardware events, use instructions as one of the sibling event. Since PERF_COUNT_HW_INSTRUCTIONS is a generic hardware event and present in all architectures, use this as third event. Reported-by: Tejas Manhas <Tejas.Manhas1@ibm.com> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Link: https://lore.kernel.org/r/20250110094620.94976-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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.