Mark Rutland 5101ef20f0 perf/arm: Special-case hetereogeneous CPUs ... Commit: 2665784850 ("perf/core: Verify we have a single perf_hw_context PMU") forcefully prevents multiple PMUs from sharing perf_hw_context, as this generally doesn't make sense. It is a common bug for uncore PMUs to use perf_hw_context rather than perf_invalid_context, which this detects. However, systems exist with heterogeneous CPUs (and hence heterogeneous HW PMUs), for which sharing perf_hw_context is necessary, and possible in some limited cases. To make this work we have to perform some gymnastics, as we did in these commits: 66eb579e66 ("perf: allow for PMU-specific event filtering") c904e32a69 ("arm: perf: filter unschedulable events") To allow those systems to work, we must allow PMUs for heterogeneous CPUs to share perf_hw_context, though we must still disallow sharing otherwise to detect the common misuse of perf_hw_context. This patch adds a new PERF_PMU_CAP_HETEROGENEOUS_CPUS for this, updates the core logic to account for this, and makes use of it in the arm_pmu code that is used for systems with heterogeneous CPUs. Comments are added to make the rationale clear and hopefully avoid accidental abuse. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20160426103346.GA20836@leverpostej Signed-off-by: Ingo Molnar <mingo@kernel.org>		2016-05-05 10:13:59 +02:00
..
callchain.c	perf core: Allow setting up max frame stack depth via sysctl	2016-04-27 10:20:39 -03:00
core.c	perf/arm: Special-case hetereogeneous CPUs	2016-05-05 10:13:59 +02:00
hw_breakpoint.c	perf: Collapse and fix event_function_call() users	2016-01-21 18:54:24 +01:00
internal.h	Linux 4.6-rc3	2016-04-13 08:57:03 +02:00
Makefile	ftrace: allow architectures to specify ftrace compile options	2015-01-29 09:19:19 +01:00
ring_buffer.c	perf/core: Add ::write_backward attribute to perf event	2016-04-23 14:12:39 +02:00
uprobes.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00