linux/arch/x86/kernel/cpu/perf_event_p6.c
Cyrill Gorcunov a072738e04 perf, x86: Implement initial P4 PMU driver
The netburst PMU is way different from the "architectural
perfomance monitoring" specification that current CPUs use.
P4 uses a tuple of ESCR+CCCR+COUNTER MSR registers to handle
perfomance monitoring events.

A few implementational details:

1) We need a separate x86_pmu::hw_config helper in struct
   x86_pmu since register bit-fields are quite different from P6,
   Core and later cpu series.

2) For the same reason is a x86_pmu::schedule_events helper
   introduced.

3) hw_perf_event::config consists of packed ESCR+CCCR values.
   It's allowed since in reality both registers only use a half
   of their size. Of course before making a real write into a
   particular MSR we need to unpack the value and extend it to
   a proper size.

4) The tuple of packed ESCR+CCCR in hw_perf_event::config
   doesn't describe the memory address of ESCR MSR register
   so that we need to keep a mapping between these tuples
   used and available ESCR (various P4 events may use same
   ESCRs but not simultaneously), for this sake every active
   event has a per-cpu map of hw_perf_event::idx <--> ESCR
   addresses.

5) Since hw_perf_event::idx is an offset to counter/control register
   we need to lift X86_PMC_MAX_GENERIC up, otherwise kernel
   strips it down to 8 registers and event armed may never be turned
   off (ie the bit in active_mask is set but the loop never reaches
   this index to check), thanks to Peter Zijlstra

Restrictions:

 - No cascaded counters support (do we ever need them?)
 - No dependent events support (so PERF_COUNT_HW_INSTRUCTIONS
   doesn't work for now)
 - There are events with same counters which can't work simultaneously
   (need to use intersected ones due to broken counter 1)
 - No PERF_COUNT_HW_CACHE_ events yet

Todo:

 - Implement dependent events
 - Need proper hashing for event opcodes (no linear search, good for
   debugging stage but not in real loads)
 - Some events counted during a clock cycle -- need to set threshold
   for them and count every clock cycle just to get summary statistics
   (ie to behave the same way as other PMUs do)
 - Need to swicth to use event_constraints
 - To support RAW events we need to encode a global list of P4 events
   into p4_templates
 - Cache events need to be added

Event support status matrix:

 Event			status
 -----------------------------
 cycles			works
 cache-references	works
 cache-misses		works
 branch-misses		works
 bus-cycles		partially (does not work on 64bit cpu with HT enabled)
 instruction		doesnt work (needs dependent event [mop tagging])
 branches		doesnt work

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100311165439.GB5129@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 18:51:08 +01:00

161 lines
3.9 KiB
C

#ifdef CONFIG_CPU_SUP_INTEL
/*
* Not sure about some of these
*/
static const u64 p6_perfmon_event_map[] =
{
[PERF_COUNT_HW_CPU_CYCLES] = 0x0079,
[PERF_COUNT_HW_INSTRUCTIONS] = 0x00c0,
[PERF_COUNT_HW_CACHE_REFERENCES] = 0x0f2e,
[PERF_COUNT_HW_CACHE_MISSES] = 0x012e,
[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x00c4,
[PERF_COUNT_HW_BRANCH_MISSES] = 0x00c5,
[PERF_COUNT_HW_BUS_CYCLES] = 0x0062,
};
static u64 p6_pmu_event_map(int hw_event)
{
return p6_perfmon_event_map[hw_event];
}
/*
* Event setting that is specified not to count anything.
* We use this to effectively disable a counter.
*
* L2_RQSTS with 0 MESI unit mask.
*/
#define P6_NOP_EVENT 0x0000002EULL
static u64 p6_pmu_raw_event(u64 hw_event)
{
#define P6_EVNTSEL_EVENT_MASK 0x000000FFULL
#define P6_EVNTSEL_UNIT_MASK 0x0000FF00ULL
#define P6_EVNTSEL_EDGE_MASK 0x00040000ULL
#define P6_EVNTSEL_INV_MASK 0x00800000ULL
#define P6_EVNTSEL_REG_MASK 0xFF000000ULL
#define P6_EVNTSEL_MASK \
(P6_EVNTSEL_EVENT_MASK | \
P6_EVNTSEL_UNIT_MASK | \
P6_EVNTSEL_EDGE_MASK | \
P6_EVNTSEL_INV_MASK | \
P6_EVNTSEL_REG_MASK)
return hw_event & P6_EVNTSEL_MASK;
}
static struct event_constraint p6_event_constraints[] =
{
INTEL_EVENT_CONSTRAINT(0xc1, 0x1), /* FLOPS */
INTEL_EVENT_CONSTRAINT(0x10, 0x1), /* FP_COMP_OPS_EXE */
INTEL_EVENT_CONSTRAINT(0x11, 0x1), /* FP_ASSIST */
INTEL_EVENT_CONSTRAINT(0x12, 0x2), /* MUL */
INTEL_EVENT_CONSTRAINT(0x13, 0x2), /* DIV */
INTEL_EVENT_CONSTRAINT(0x14, 0x1), /* CYCLES_DIV_BUSY */
EVENT_CONSTRAINT_END
};
static void p6_pmu_disable_all(void)
{
u64 val;
/* p6 only has one enable register */
rdmsrl(MSR_P6_EVNTSEL0, val);
val &= ~ARCH_PERFMON_EVENTSEL_ENABLE;
wrmsrl(MSR_P6_EVNTSEL0, val);
}
static void p6_pmu_enable_all(void)
{
unsigned long val;
/* p6 only has one enable register */
rdmsrl(MSR_P6_EVNTSEL0, val);
val |= ARCH_PERFMON_EVENTSEL_ENABLE;
wrmsrl(MSR_P6_EVNTSEL0, val);
}
static inline void
p6_pmu_disable_event(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
u64 val = P6_NOP_EVENT;
if (cpuc->enabled)
val |= ARCH_PERFMON_EVENTSEL_ENABLE;
(void)checking_wrmsrl(hwc->config_base + hwc->idx, val);
}
static void p6_pmu_enable_event(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
u64 val;
val = hwc->config;
if (cpuc->enabled)
val |= ARCH_PERFMON_EVENTSEL_ENABLE;
(void)checking_wrmsrl(hwc->config_base + hwc->idx, val);
}
static __initconst struct x86_pmu p6_pmu = {
.name = "p6",
.handle_irq = x86_pmu_handle_irq,
.disable_all = p6_pmu_disable_all,
.enable_all = p6_pmu_enable_all,
.enable = p6_pmu_enable_event,
.disable = p6_pmu_disable_event,
.hw_config = x86_hw_config,
.schedule_events = x86_schedule_events,
.eventsel = MSR_P6_EVNTSEL0,
.perfctr = MSR_P6_PERFCTR0,
.event_map = p6_pmu_event_map,
.raw_event = p6_pmu_raw_event,
.max_events = ARRAY_SIZE(p6_perfmon_event_map),
.apic = 1,
.max_period = (1ULL << 31) - 1,
.version = 0,
.num_events = 2,
/*
* Events have 40 bits implemented. However they are designed such
* that bits [32-39] are sign extensions of bit 31. As such the
* effective width of a event for P6-like PMU is 32 bits only.
*
* See IA-32 Intel Architecture Software developer manual Vol 3B
*/
.event_bits = 32,
.event_mask = (1ULL << 32) - 1,
.get_event_constraints = x86_get_event_constraints,
.event_constraints = p6_event_constraints,
};
static __init int p6_pmu_init(void)
{
switch (boot_cpu_data.x86_model) {
case 1:
case 3: /* Pentium Pro */
case 5:
case 6: /* Pentium II */
case 7:
case 8:
case 11: /* Pentium III */
case 9:
case 13:
/* Pentium M */
break;
default:
pr_cont("unsupported p6 CPU model %d ",
boot_cpu_data.x86_model);
return -ENODEV;
}
x86_pmu = p6_pmu;
return 0;
}
#endif /* CONFIG_CPU_SUP_INTEL */