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Date: Tue, 1 Jul 2014 23:46:55 +0200
From: Thomas Schoebel-Theuer <tst@...oebel-theuer.de>
To: linux-kernel@...r.kernel.org
Subject: [PATCH 15/50] mars: add new file include/linux/brick/lib_timing.h
Signed-off-by: Thomas Schoebel-Theuer <tst@...oebel-theuer.de>
---
include/linux/brick/lib_timing.h | 156 +++++++++++++++++++++++++++++++++++++++
1 file changed, 156 insertions(+)
create mode 100644 include/linux/brick/lib_timing.h
diff --git a/include/linux/brick/lib_timing.h b/include/linux/brick/lib_timing.h
new file mode 100644
index 0000000..af15f1a
--- /dev/null
+++ b/include/linux/brick/lib_timing.h
@@ -0,0 +1,156 @@
+/* (c) 2012 Thomas Schoebel-Theuer / 1&1 Internet AG */
+#ifndef BRICK_LIB_TIMING_H
+#define BRICK_LIB_TIMING_H
+
+#include <linux/brick/brick.h>
+
+#include <linux/sched.h>
+
+/* Simple infrastructure for timing of arbitrary operations and creation
+ * of some simple histogram statistics.
+ */
+
+#define TIMING_MAX 24
+
+struct timing_stats {
+#ifdef CONFIG_MARS_DEBUG
+ int tim_count[TIMING_MAX];
+
+#endif
+};
+
+#define _TIME_THIS(_stamp1, _stamp2, _CODE) \
+ ({ \
+ (_stamp1) = cpu_clock(raw_smp_processor_id()); \
+ \
+ _CODE; \
+ \
+ (_stamp2) = cpu_clock(raw_smp_processor_id()); \
+ (_stamp2) - (_stamp1); \
+ })
+
+#define TIME_THIS(_CODE) \
+ ({ \
+ unsigned long long _stamp1; \
+ unsigned long long _stamp2; \
+ _TIME_THIS(_stamp1, _stamp2, _CODE); \
+ })
+
+#ifdef CONFIG_MARS_DEBUG
+
+#define _TIME_STATS(_timing, _stamp1, _stamp2, _CODE) \
+ ({ \
+ unsigned long long _time; \
+ unsigned long _tmp; \
+ int _i; \
+ \
+ _time = _TIME_THIS(_stamp1, _stamp2, _CODE); \
+ \
+ _tmp = _time / 1000; /* convert to us */ \
+ _i = 0; \
+ while (_tmp > 0 && _i < TIMING_MAX - 1) { \
+ _tmp >>= 1; \
+ _i++; \
+ } \
+ (_timing)->tim_count[_i]++; \
+ _time; \
+ })
+
+#define TIME_STATS(_timing, _CODE) \
+ ({ \
+ unsigned long long _stamp1; \
+ unsigned long long _stamp2; \
+ _TIME_STATS(_timing, _stamp1, _stamp2, _CODE); \
+ })
+
+extern int report_timing(struct timing_stats *tim, char *str, int maxlen);
+
+#else /* CONFIG_MARS_DEBUG */
+
+#define _TIME_STATS(_timing, _stamp1, _stamp2, _CODE) \
+ ((void)_timing, (_stamp1) = (_stamp2) = cpu_clock(raw_smp_processor_id()), _CODE, 0)
+
+#define TIME_STATS(_timing, _CODE) \
+ ((void)_timing, _CODE, 0)
+
+#define report_timing(tim, str, maxlen) ((void)tim, 0)
+
+#endif /* CONFIG_MARS_DEBUG */
+
+/* A banning represents some overloaded resource.
+ *
+ * Whenever overload is detected, you should call banning_hit()
+ * telling that the overload is assumed / estimated to continue
+ * for some duration in time.
+ *
+ * ATTENTION! These operations are deliberately raceful.
+ * They are meant to deliver _hints_ (e.g. for IO scheduling
+ * decisions etc), not hard facts!
+ *
+ * If you need locking, just surround these operations
+ * with locking by yourself.
+ */
+struct banning {
+ long long ban_last_hit;
+
+ /* statistical */
+ int ban_renew_count;
+ int ban_count;
+};
+
+extern inline
+bool banning_hit(struct banning *ban, long long duration)
+{
+ long long now = cpu_clock(raw_smp_processor_id());
+ bool hit = ban->ban_last_hit >= now;
+ long long new_hit = now + duration;
+
+ ban->ban_renew_count++;
+ if (!ban->ban_last_hit || ban->ban_last_hit < new_hit) {
+ ban->ban_last_hit = new_hit;
+ ban->ban_count++;
+ }
+ return hit;
+}
+
+extern inline
+bool banning_is_hit(struct banning *ban)
+{
+ long long now = cpu_clock(raw_smp_processor_id());
+
+ return (ban->ban_last_hit && ban->ban_last_hit >= now);
+}
+
+extern inline
+void banning_reset(struct banning *ban)
+{
+ ban->ban_last_hit = 0;
+}
+
+/* Threshold: trigger a banning whenever some latency threshold
+ * is exceeded.
+ */
+struct threshold {
+ struct banning *thr_ban;
+
+ /* tunables */
+ int thr_limit; /* in us */
+ int thr_factor; /* in % */
+ int thr_plus; /* in us */
+ /* statistical */
+ int thr_triggered;
+ int thr_true_hit;
+};
+
+extern inline
+void threshold_check(struct threshold *thr, long long latency)
+{
+ if (thr->thr_limit &&
+ latency > (long long)thr->thr_limit * 1000) {
+ thr->thr_triggered++;
+ if (!banning_hit(thr->thr_ban, latency * thr->thr_factor / 100 + thr->thr_plus * 1000))
+ thr->thr_true_hit++;
+ }
+}
+
+#endif
--
2.0.0
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