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Message-Id: <1455152873-30467-4-git-send-email-vikas.shivappa@linux.intel.com>
Date: Wed, 10 Feb 2016 17:07:51 -0800
From: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
To: vikas.shivappa@...el.com
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, hpa@...or.com,
tglx@...utronix.de, vikas.shivappa@...ux.intel.com,
mingo@...nel.org, peterz@...radead.org, ravi.v.shankar@...el.com,
tony.luck@...el.com, fenghua.yu@...el.com,
kanaka.d.juvva@...el.com, h.peter.anvin@...el.com
Subject: [PATCH 3/5] x86/mbm: Memory bandwidth monitoring event management
From: Tony Luck<tony.luck@...el.com>
Includes all the core infrastructure to measure the total_bytes and
bandwidth.
We have per socket counters for both total system wide L3 external bytes
and local socket memory-controller bytes. The current b/w is calculated
for a minimum diff time(time since it was last counted) of 100ms. The OS
does MSR writes to MSR_IA32_QM_EVTSEL and MSR_IA32_QM_CTR to read the
counters and uses the IA32_PQR_ASSOC_MSR to associate the RMID with
the task. The tasks have a common RMID for cqm(cache quality of
service monitoring) and MBM. Hence most of the scheduling code is
reused from cqm.
Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
---
arch/x86/kernel/cpu/perf_event_intel_cqm.c | 159 ++++++++++++++++++++++++++++-
1 file changed, 155 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
index e45f5aa..b1c9663 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
@@ -13,6 +13,11 @@
#define MSR_IA32_QM_CTR 0x0c8e
#define MSR_IA32_QM_EVTSEL 0x0c8d
+/*
+ * MBM Counter is 24bits wide. MBM_CNTR_MAX defines max counter
+ * value
+ */
+#define MBM_CNTR_MAX 0xffffff
static u32 cqm_max_rmid = -1;
static unsigned int cqm_l3_scale; /* supposedly cacheline size */
static bool cqm_enabled, mbm_enabled;
@@ -69,6 +74,16 @@ static struct sample *mbm_total;
*/
static struct sample *mbm_local;
+#define pkg_id topology_physical_package_id(smp_processor_id())
+/*
+ * rmid_2_index returns the index for the rmid in mbm_local/mbm_total array.
+ * mbm_total[] and mbm_local[] are linearly indexed by socket# * max number of
+ * rmids per socket, an example is given below
+ * RMID1 of Socket0: vrmid = 1
+ * RMID1 of Socket1: vrmid = 1 * (cqm_max_rmid + 1) + 1
+ * RMID1 of Socket2: vrmid = 2 * (cqm_max_rmid + 1) + 1
+ */
+#define rmid_2_index(rmid) ((pkg_id * (cqm_max_rmid + 1)) + rmid)
/*
* Protects cache_cgroups and cqm_rmid_free_lru and cqm_rmid_limbo_lru.
* Also protects event->hw.cqm_rmid
@@ -92,8 +107,19 @@ static cpumask_t cqm_cpumask;
#define RMID_VAL_UNAVAIL (1ULL << 62)
#define QOS_L3_OCCUP_EVENT_ID (1 << 0)
+/*
+ * MBM Event IDs as defined in SDM section 17.15.5
+ * Event IDs are used to program EVTSEL MSRs before reading mbm event counters
+ */
+enum mbm_evt_type {
+ QOS_MBM_TOTAL_EVENT_ID = 0x02,
+ QOS_MBM_LOCAL_EVENT_ID,
+ QOS_MBM_TOTAL_BW_EVENT_ID,
+ QOS_MBM_LOCAL_BW_EVENT_ID,
+};
-#define QOS_EVENT_MASK QOS_L3_OCCUP_EVENT_ID
+#define QOS_MBM_BW_EVENT_MASK 0x04
+#define QOS_MBM_LOCAL_EVENT_MASK 0x01
/*
* This is central to the rotation algorithm in __intel_cqm_rmid_rotate().
@@ -423,9 +449,16 @@ static bool __conflict_event(struct perf_event *a, struct perf_event *b)
struct rmid_read {
u32 rmid;
atomic64_t value;
+ enum mbm_evt_type evt_type;
};
static void __intel_cqm_event_count(void *info);
+static void init_mbm_sample(u32 rmid, enum mbm_evt_type evt_type);
+
+static bool is_mbm_event(int e)
+{
+ return (e >= QOS_MBM_TOTAL_EVENT_ID && e <= QOS_MBM_LOCAL_BW_EVENT_ID);
+}
/*
* Exchange the RMID of a group of events.
@@ -867,6 +900,98 @@ static void intel_cqm_rmid_rotate(struct work_struct *work)
schedule_delayed_work(&intel_cqm_rmid_work, delay);
}
+static struct sample *update_sample(unsigned int rmid,
+ enum mbm_evt_type evt_type, int first)
+{
+ ktime_t cur_time;
+ struct sample *mbm_current;
+ u32 vrmid = rmid_2_index(rmid);
+ u64 val, bytes, diff_time;
+ u32 eventid;
+
+ if (evt_type & QOS_MBM_LOCAL_EVENT_MASK) {
+ mbm_current = &mbm_local[vrmid];
+ eventid = QOS_MBM_LOCAL_EVENT_ID;
+ } else {
+ mbm_current = &mbm_total[vrmid];
+ eventid = QOS_MBM_TOTAL_EVENT_ID;
+ }
+
+ cur_time = ktime_get();
+ wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid);
+ rdmsrl(MSR_IA32_QM_CTR, val);
+ if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
+ return mbm_current;
+ val &= MBM_CNTR_MAX;
+
+ if (first) {
+ mbm_current->interval_start = cur_time;
+ mbm_current->prev_msr = val;
+ mbm_current->total_bytes = 0;
+ mbm_current->interval_bytes = 0;
+ mbm_current->bandwidth = 0;
+ return mbm_current;
+ }
+
+ if (val < mbm_current->prev_msr)
+ bytes = MBM_CNTR_MAX - mbm_current->prev_msr + val + 1;
+ else
+ bytes = val - mbm_current->prev_msr;
+ bytes *= cqm_l3_scale;
+
+ mbm_current->total_bytes += bytes;
+ mbm_current->interval_bytes += bytes;
+ mbm_current->prev_msr = val;
+ diff_time = ktime_ms_delta(cur_time, mbm_current->interval_start);
+
+ /*
+ * The b/w measured is really the most recent/current b/w.
+ * We wait till enough time has passed to avoid
+ * arthmetic rounding problems.Having it at >=100ms,
+ * such errors would be <=1%.
+ */
+ if (diff_time > 100) {
+ bytes = mbm_current->interval_bytes * MSEC_PER_SEC;
+ do_div(bytes, diff_time);
+ mbm_current->bandwidth = bytes;
+ mbm_current->interval_bytes = 0;
+ mbm_current->interval_start = cur_time;
+ }
+
+ return mbm_current;
+}
+
+static u64 rmid_read_mbm(unsigned int rmid, enum mbm_evt_type evt_type)
+{
+ struct sample *mbm_current;
+
+ mbm_current = update_sample(rmid, evt_type, 0);
+
+ if (evt_type & QOS_MBM_BW_EVENT_MASK)
+ return mbm_current->bandwidth;
+ else
+ return mbm_current->total_bytes;
+}
+
+static void __intel_mbm_event_init(void *info)
+{
+ struct rmid_read *rr = info;
+
+ update_sample(rr->rmid, rr->evt_type, 1);
+}
+
+static void init_mbm_sample(u32 rmid, enum mbm_evt_type evt_type)
+{
+ struct rmid_read rr = {
+ .value = ATOMIC64_INIT(0),
+ };
+
+ rr.rmid = rmid;
+ rr.evt_type = evt_type;
+ /* on each socket, init sample */
+ on_each_cpu_mask(&cqm_cpumask, __intel_mbm_event_init, &rr, 1);
+}
+
/*
* Find a group and setup RMID.
*
@@ -887,6 +1012,9 @@ static void intel_cqm_setup_event(struct perf_event *event,
/* All tasks in a group share an RMID */
event->hw.cqm_rmid = rmid;
*group = iter;
+ if (is_mbm_event(event->attr.config) &&
+ __rmid_valid(rmid))
+ init_mbm_sample(rmid, event->attr.config);
return;
}
@@ -903,6 +1031,9 @@ static void intel_cqm_setup_event(struct perf_event *event,
else
rmid = __get_rmid();
+ if (is_mbm_event(event->attr.config) && __rmid_valid(rmid))
+ init_mbm_sample(rmid, event->attr.config);
+
event->hw.cqm_rmid = rmid;
}
@@ -924,7 +1055,10 @@ static void intel_cqm_event_read(struct perf_event *event)
if (!__rmid_valid(rmid))
goto out;
- val = __rmid_read(rmid);
+ if (is_mbm_event(event->attr.config))
+ val = rmid_read_mbm(rmid, event->attr.config);
+ else
+ val = __rmid_read(rmid);
/*
* Ignore this reading on error states and do not update the value.
@@ -955,6 +1089,17 @@ static inline bool cqm_group_leader(struct perf_event *event)
return !list_empty(&event->hw.cqm_groups_entry);
}
+static void __intel_mbm_event_count(void *info)
+{
+ struct rmid_read *rr = info;
+ u64 val;
+
+ val = rmid_read_mbm(rr->rmid, rr->evt_type);
+ if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
+ return;
+ atomic64_add(val, &rr->value);
+}
+
static u64 intel_cqm_event_count(struct perf_event *event)
{
unsigned long flags;
@@ -1008,7 +1153,12 @@ static u64 intel_cqm_event_count(struct perf_event *event)
if (!__rmid_valid(rr.rmid))
goto out;
- on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, &rr, 1);
+ if (is_mbm_event(event->attr.config)) {
+ rr.evt_type = event->attr.config;
+ on_each_cpu_mask(&cqm_cpumask, __intel_mbm_event_count, &rr, 1);
+ } else {
+ on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, &rr, 1);
+ }
raw_spin_lock_irqsave(&cache_lock, flags);
if (event->hw.cqm_rmid == rr.rmid)
@@ -1123,7 +1273,8 @@ static int intel_cqm_event_init(struct perf_event *event)
if (event->attr.type != intel_cqm_pmu.type)
return -ENOENT;
- if (event->attr.config & ~QOS_EVENT_MASK)
+ if ((event->attr.config < QOS_L3_OCCUP_EVENT_ID) ||
+ (event->attr.config > QOS_MBM_LOCAL_BW_EVENT_ID))
return -EINVAL;
/* unsupported modes and filters */
--
1.9.1
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