perf_events: Update Intel extra regs shared constraints management

This patch improves the code managing the extra shared registers
used for offcore_response events on Intel Nehalem/Westmere. The
idea is to use static allocation instead of dynamic allocation.
This simplifies greatly the get and put constraint routines for
those events.

The patch also renames per_core to shared_regs because the same
data structure gets used whether or not HT is on. When HT is
off, those events still need to coordination because they use
a extra MSR that has to be shared within an event group.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110606145703.GA7258@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 11 insertions, 3 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 771b0b2845e4..069315eefb22 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -536,6 +536,16 @@ struct perf_branch_stack {
 
 struct task_struct;
 
+/*
+ * extra PMU register associated with an event
+ */
+struct hw_perf_event_extra {
+	u64		config;	/* register value */
+	unsigned int	reg;	/* register address or index */
+	int		alloc;	/* extra register already allocated */
+	int		idx;	/* index in shared_regs->regs[] */
+};
+
 /**
  * struct hw_perf_event - performance event hardware details:
  */
@@ -549,9 +559,7 @@ struct hw_perf_event {
 			unsigned long	event_base;
 			int		idx;
 			int		last_cpu;
-			unsigned int	extra_reg;
-			u64		extra_config;
-			int		extra_alloc;
+			struct hw_perf_event_extra extra_reg;
 		};
 		struct { /* software */
 			struct hrtimer	hrtimer;