Latency measurements, compiled out of production code.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@736135 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 151 insertions, 0 deletions

diff --git a/cpp/src/qpid/sys/LatencyMetric.cpp b/cpp/src/qpid/sys/LatencyMetric.cpp
new file mode 100644
index 0000000000..93fd852d64
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+++ b/cpp/src/qpid/sys/LatencyMetric.cpp
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+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+
+#ifdef QPID_LATENCY_METRIC
+
+#include "LatencyMetric.h"
+#include "Time.h"
+#include <iostream>
+
+namespace qpid {
+namespace sys {
+
+void LatencyMetricTimestamp::initialize(const LatencyMetricTimestamp& ts) {
+    const_cast<int64_t&>(ts.latency_metric_timestamp) = Duration(now());
+}
+
+LatencyMetric::LatencyMetric(const char* msg, int64_t skip_) : 
+    message(msg), count(0), total(0), skipped(0), skip(skip_)
+{}
+
+LatencyMetric::~LatencyMetric() { report(); }
+    
+void LatencyMetric::record(const LatencyMetricTimestamp& start) {
+    Mutex::ScopedLock l(lock);  // FIXME aconway 2009-01-20: atomics?
+    if (!start.latency_metric_timestamp) return; // Ignore 0 timestamps.
+    if (skip) {
+        if (++skipped < skip) return;
+        else skipped = 0;
+    }
+    ++count;
+    int64_t now_ = Duration(now());
+    total += now_ - start.latency_metric_timestamp;
+    // Set start time for next leg of the journey 
+    const_cast<int64_t&>(start.latency_metric_timestamp) = now_; 
+}
+
+void LatencyMetric::report() {
+    using namespace std;
+    if (count) {
+        cout << "LATENCY: " << message << ": "
+             << total / (count * TIME_USEC) << " microseconds" << endl;
+    }
+    else {
+        cout << "LATENCY: " << message << ": no data." << endl;
+    }
+    count = 0;
+    total = 0; 
+}
+
+
+}} // namespace qpid::sys
+
+#endif 
diff --git a/cpp/src/qpid/sys/LatencyMetric.h b/cpp/src/qpid/sys/LatencyMetric.h
new file mode 100644
index 0000000000..f2ab1ec5e1
--- /dev/null
+++ b/cpp/src/qpid/sys/LatencyMetric.h
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+#ifndef QPID_SYS_LATENCYMETRIC_H
+#define QPID_SYS_LATENCYMETRIC_H
+
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+
+#ifdef QPID_LATENCY_METRIC
+
+#include "qpid/sys/IntegerTypes.h"
+#include "qpid/sys/Mutex.h"
+
+namespace qpid {
+namespace sys {
+
+/** Use this base class to add a timestamp for latency to an object */
+struct LatencyMetricTimestamp {
+    LatencyMetricTimestamp() : latency_metric_timestamp(0) {}
+    static void initialize(const LatencyMetricTimestamp&);
+    int64_t latency_metric_timestamp;
+};
+    
+/**
+ * Record average latencies, report on destruction.
+ *
+ * For debugging only, use via macros below so it can be compiled out
+ * of production code.
+ */
+class LatencyMetric {
+  public:
+    /** msg should be a string literal. */
+    LatencyMetric(const char* msg, int64_t skip_=0);
+    ~LatencyMetric();
+    
+    void record(const LatencyMetricTimestamp& start);
+
+  private:
+    void report();
+    Mutex lock;
+    const char* message;
+    int64_t ignore, count, total, skipped, skip;
+};
+
+}} // namespace qpid::sys
+
+#define QPID_LATENCY_INIT(x) ::qpid::sys::LatencyMetricTimestamp::initialize(x)
+#define QPID_LATENCY_RECORD(msg, x) do {                                 \
+        static ::qpid::sys::LatencyMetric metric__(msg); metric__.record(x); \
+    } while (false)
+
+
+#else  /* defined QPID_LATENCY_METRIC */
+
+namespace qpid { namespace sys {
+class LatencyMetricTimestamp {};
+}}
+
+#define QPID_LATENCY_INIT(x) (void)x
+#define QPID_LATENCY_RECORD(msg, x) (void)x
+
+#endif /* defined QPID_LATENCY_METRIC */
+
+#endif  /*!QPID_SYS_LATENCYMETRIC_H*/