diff options
| author | Wolfgang Bumiller <w.bumiller@proxmox.com> | 2018-02-07 08:17:58 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2018-02-15 09:39:49 +0000 |
| commit | b7728f32216f0a7a87bee2f4e009e68b00fd4fb5 (patch) | |
| tree | 06bdfc37b12614beba4dc3a48131a55517ccb904 | |
| parent | 00d09fdbbae5f7864ce754913efc84c12fdf9f1a (diff) | |
ratelimit: don't align wait time with slices
It is possible for rate limited writes to keep overshooting a slice's
quota by a tiny amount causing the slice-aligned waiting period to
effectively halve the rate.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180207071758.6818-1-w.bumiller@proxmox.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | include/qemu/ratelimit.h | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/include/qemu/ratelimit.h b/include/qemu/ratelimit.h index 8dece483f5..1b38291823 100644 --- a/include/qemu/ratelimit.h +++ b/include/qemu/ratelimit.h @@ -36,7 +36,7 @@ typedef struct { static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n) { int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); - uint64_t delay_slices; + double delay_slices; assert(limit->slice_quota && limit->slice_ns); @@ -55,12 +55,11 @@ static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n) return 0; } - /* Quota exceeded. Calculate the next time slice we may start - * sending data again. */ - delay_slices = (limit->dispatched + limit->slice_quota - 1) / - limit->slice_quota; + /* Quota exceeded. Wait based on the excess amount and then start a new + * slice. */ + delay_slices = (double)limit->dispatched / limit->slice_quota; limit->slice_end_time = limit->slice_start_time + - delay_slices * limit->slice_ns; + (uint64_t)(delay_slices * limit->slice_ns); return limit->slice_end_time - now; } |