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| author | Nicholas Piggin <npiggin@gmail.com> | 2021-11-23 10:51:50 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-11-24 11:08:57 +0100 |
| commit | 0a4b4327ce867e3ac1b3ad15f4d2b686b516b3a2 (patch) | |
| tree | 5862cf843d3d5613ac58bbbd28d7acb57523823a /Documentation/admin-guide | |
| parent | powerpc/64s: Always set PMU control registers to frozen/disabled when not in use (diff) | |
| download | linux-0a4b4327ce867e3ac1b3ad15f4d2b686b516b3a2.tar.xz linux-0a4b4327ce867e3ac1b3ad15f4d2b686b516b3a2.zip | |
powerpc/64s: Implement PMU override command line option
It can be useful in simulators (with very constrained environments)
to allow some PMCs to run from boot so they can be sampled directly
by a test harness, rather than having to run perf.
A previous change freezes counters at boot by default, so provide
a boot time option to un-freeze (plus a bit more flexibility).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-13-npiggin@gmail.com
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9725c546a0d4..2711ddb4835a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4144,6 +4144,14 @@ Override pmtimer IOPort with a hex value. e.g. pmtmr=0x508 + pmu_override= [PPC] Override the PMU. + This option takes over the PMU facility, so it is no + longer usable by perf. Setting this option starts the + PMU counters by setting MMCR0 to 0 (the FC bit is + cleared). If a number is given, then MMCR1 is set to + that number, otherwise (e.g., 'pmu_override=on'), MMCR1 + remains 0. + pm_debug_messages [SUSPEND,KNL] Enable suspend/resume debug messages during boot up. |