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authorAlberto Garcia <berto@igalia.com>2015-10-28 17:33:01 +0200
committerKevin Wolf <kwolf@redhat.com>2015-11-12 16:22:45 +0100
commitbd797fc15b4290e02c219b7cd6289a33cd6cd18b (patch)
tree04242c8d6097bba0e8f4f19ec0097b0a935d39f0 /include/qemu
parent5519593c07c71c55b196546a00c08106bd9a100b (diff)
downloadhqemu-bd797fc15b4290e02c219b7cd6289a33cd6cd18b.zip
hqemu-bd797fc15b4290e02c219b7cd6289a33cd6cd18b.tar.gz
util: Infrastructure for computing recent averages
This module computes the average of a set of values within a time window, keeping also track of the minimum and maximum values. In order to produce more accurate results it works internally by creating two time windows of the same period, offsetted by half of that period. Values are accounted on both windows and the data is always returned from the oldest one. [Add missing util/replay.o to test-timed-average dependencies to fix the build. --Stefan] Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 201b09c21bbc9c329779d2b2365ee2b9c80dceeb.1446044837.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include/qemu')
-rw-r--r--include/qemu/timed-average.h63
1 files changed, 63 insertions, 0 deletions
diff --git a/include/qemu/timed-average.h b/include/qemu/timed-average.h
new file mode 100644
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--- /dev/null
+++ b/include/qemu/timed-average.h
@@ -0,0 +1,63 @@
+/*
+ * QEMU timed average computation
+ *
+ * Copyright (C) Nodalink, EURL. 2014
+ * Copyright (C) Igalia, S.L. 2015
+ *
+ * Authors:
+ * BenoƮt Canet <benoit.canet@nodalink.com>
+ * Alberto Garcia <berto@igalia.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) version 3 or any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TIMED_AVERAGE_H
+#define TIMED_AVERAGE_H
+
+#include <stdint.h>
+
+#include "qemu/timer.h"
+
+typedef struct TimedAverageWindow TimedAverageWindow;
+typedef struct TimedAverage TimedAverage;
+
+/* All fields of both structures are private */
+
+struct TimedAverageWindow {
+ uint64_t min; /* minimum value accounted in the window */
+ uint64_t max; /* maximum value accounted in the window */
+ uint64_t sum; /* sum of all values */
+ uint64_t count; /* number of values */
+ int64_t expiration; /* the end of the current window in ns */
+};
+
+struct TimedAverage {
+ uint64_t period; /* period in nanoseconds */
+ TimedAverageWindow windows[2]; /* two overlapping windows of with
+ * an offset of period / 2 between them */
+ unsigned current; /* the current window index: it's also the
+ * oldest window index */
+ QEMUClockType clock_type; /* the clock used */
+};
+
+void timed_average_init(TimedAverage *ta, QEMUClockType clock_type,
+ uint64_t period);
+
+void timed_average_account(TimedAverage *ta, uint64_t value);
+
+uint64_t timed_average_min(TimedAverage *ta);
+uint64_t timed_average_avg(TimedAverage *ta);
+uint64_t timed_average_max(TimedAverage *ta);
+
+#endif
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