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Subject[tip:perf/core] perf, intel: Try alternative OFFCORE encodings
Commit-ID:  b79e8941fb9af07d810da91b4e29da2bba331b6e
Gitweb: http://git.kernel.org/tip/b79e8941fb9af07d810da91b4e29da2bba331b6e
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Mon, 23 May 2011 11:08:15 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 1 Jul 2011 11:06:37 +0200

perf, intel: Try alternative OFFCORE encodings

Since the OFFCORE registers are fully symmetric, try the other one
when the specified one is already in use.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1306141897.18455.8.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/perf_event.c | 5 +++-
arch/x86/kernel/cpu/perf_event_intel.c | 44 ++++++++++++++++++++++++++-----
2 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 583f311..c53d433 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -327,9 +327,12 @@ struct x86_pmu {
* Extra registers for events
*/
struct extra_reg *extra_regs;
- bool regs_no_ht_sharing;
+ unsigned int er_flags;
};

+#define ERF_NO_HT_SHARING 1
+#define ERF_HAS_RSP_1 2
+
static struct x86_pmu x86_pmu __read_mostly;

static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index a674ae4..5c44862 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1018,6 +1018,29 @@ intel_bts_constraints(struct perf_event *event)
return NULL;
}

+static bool intel_try_alt_er(struct perf_event *event, int orig_idx)
+{
+ if (!(x86_pmu.er_flags & ERF_HAS_RSP_1))
+ return false;
+
+ if (event->hw.extra_reg.idx == EXTRA_REG_RSP_0) {
+ event->hw.config &= ~INTEL_ARCH_EVENT_MASK;
+ event->hw.config |= 0x01bb;
+ event->hw.extra_reg.idx = EXTRA_REG_RSP_1;
+ event->hw.extra_reg.reg = MSR_OFFCORE_RSP_1;
+ } else if (event->hw.extra_reg.idx == EXTRA_REG_RSP_1) {
+ event->hw.config &= ~INTEL_ARCH_EVENT_MASK;
+ event->hw.config |= 0x01b7;
+ event->hw.extra_reg.idx = EXTRA_REG_RSP_0;
+ event->hw.extra_reg.reg = MSR_OFFCORE_RSP_0;
+ }
+
+ if (event->hw.extra_reg.idx == orig_idx)
+ return false;
+
+ return true;
+}
+
/*
* manage allocation of shared extra msr for certain events
*
@@ -1027,16 +1050,19 @@ intel_bts_constraints(struct perf_event *event)
*/
static struct event_constraint *
__intel_shared_reg_get_constraints(struct cpu_hw_events *cpuc,
- struct hw_perf_event_extra *reg)
+ struct perf_event *event)
{
struct event_constraint *c = &emptyconstraint;
+ struct hw_perf_event_extra *reg = &event->hw.extra_reg;
struct er_account *era;
unsigned long flags;
+ int orig_idx = reg->idx;

/* already allocated shared msr */
if (reg->alloc)
return &unconstrained;

+again:
era = &cpuc->shared_regs->regs[reg->idx];
/*
* we use spin_lock_irqsave() to avoid lockdep issues when
@@ -1065,6 +1091,9 @@ __intel_shared_reg_get_constraints(struct cpu_hw_events *cpuc,
* the regular event constraint table.
*/
c = &unconstrained;
+ } else if (intel_try_alt_er(event, orig_idx)) {
+ raw_spin_unlock(&era->lock);
+ goto again;
}
raw_spin_unlock_irqrestore(&era->lock, flags);

@@ -1099,11 +1128,10 @@ intel_shared_regs_constraints(struct cpu_hw_events *cpuc,
struct perf_event *event)
{
struct event_constraint *c = NULL;
- struct hw_perf_event_extra *xreg;

- xreg = &event->hw.extra_reg;
- if (xreg->idx != EXTRA_REG_NONE)
- c = __intel_shared_reg_get_constraints(cpuc, xreg);
+ if (event->hw.extra_reg.idx != EXTRA_REG_NONE)
+ c = __intel_shared_reg_get_constraints(cpuc, event);
+
return c;
}

@@ -1264,7 +1292,7 @@ static void intel_pmu_cpu_starting(int cpu)
*/
intel_pmu_lbr_reset();

- if (!cpuc->shared_regs || x86_pmu.regs_no_ht_sharing)
+ if (!cpuc->shared_regs || (x86_pmu.er_flags & ERF_NO_HT_SHARING))
return;

for_each_cpu(i, topology_thread_cpumask(cpu)) {
@@ -1489,6 +1517,7 @@ static __init int intel_pmu_init(void)
x86_pmu.enable_all = intel_pmu_nhm_enable_all;
x86_pmu.pebs_constraints = intel_westmere_pebs_event_constraints;
x86_pmu.extra_regs = intel_westmere_extra_regs;
+ x86_pmu.er_flags |= ERF_HAS_RSP_1;

/* UOPS_ISSUED.STALLED_CYCLES */
intel_perfmon_event_map[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = 0x180010e;
@@ -1508,7 +1537,8 @@ static __init int intel_pmu_init(void)
x86_pmu.pebs_constraints = intel_snb_pebs_events;
x86_pmu.extra_regs = intel_snb_extra_regs;
/* all extra regs are per-cpu when HT is on */
- x86_pmu.regs_no_ht_sharing = true;
+ x86_pmu.er_flags |= ERF_HAS_RSP_1;
+ x86_pmu.er_flags |= ERF_NO_HT_SHARING;

/* UOPS_ISSUED.ANY,c=1,i=1 to count stall cycles */
intel_perfmon_event_map[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = 0x180010e;

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