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authorPaolo Bonzini <pbonzini@redhat.com>2012-05-09 16:09:46 +0200
committerKevin Wolf <kwolf@redhat.com>2012-06-15 14:03:42 +0200
commit6ef228fc0de1d5fb43ebfef039563d39a3a37067 (patch)
tree86b1d3979c5f45a723277ca067a4f1a0dd4661d6 /include/qemu/ratelimit.h
parent188a7bbf94aa53019ef7d2438c8e9d900e590091 (diff)
downloadqemu-arm-6ef228fc0de1d5fb43ebfef039563d39a3a37067.tar.gz
stream: move rate limiting to a separate header file
Make the code reusable. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include/qemu/ratelimit.h')
-rw-r--r--include/qemu/ratelimit.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/include/qemu/ratelimit.h b/include/qemu/ratelimit.h
new file mode 100644
index 0000000000..c6ac281141
--- /dev/null
+++ b/include/qemu/ratelimit.h
@@ -0,0 +1,48 @@
+/*
+ * Ratelimiting calculations
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_RATELIMIT_H
+#define QEMU_RATELIMIT_H 1
+
+typedef struct {
+ int64_t next_slice_time;
+ uint64_t slice_quota;
+ uint64_t slice_ns;
+ uint64_t dispatched;
+} RateLimit;
+
+static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n)
+{
+ int64_t now = qemu_get_clock_ns(rt_clock);
+
+ if (limit->next_slice_time < now) {
+ limit->next_slice_time = now + limit->slice_ns;
+ limit->dispatched = 0;
+ }
+ if (limit->dispatched == 0 || limit->dispatched + n <= limit->slice_quota) {
+ limit->dispatched += n;
+ return 0;
+ } else {
+ limit->dispatched = n;
+ return limit->next_slice_time - now;
+ }
+}
+
+static inline void ratelimit_set_speed(RateLimit *limit, uint64_t speed,
+ uint64_t slice_ns)
+{
+ limit->slice_ns = slice_ns;
+ limit->slice_quota = ((double)speed * 1000000000ULL) / slice_ns;
+}
+
+#endif