xemu/include/qemu/ratelimit.h

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/*
* 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_clock_get_ns(QEMU_CLOCK_REALTIME);
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 * slice_ns)/1000000000ULL;
}
#endif