commit 3e9fab690d59ac15956c3733fe0794ce1ae4c4af
author Benoît Canet <benoit@irqsave.net> Mon Sep 02 14:14:40 2013 +0200
committer Stefan Hajnoczi <stefanha@redhat.com> Fri Sep 06 15:25:07 2013 +0200
tree 0d7b4d55ff9a3664091148713c5a5bc3e2a02c8d
parent cc0681c45430a1f1a4c2d06e9499b7775afc9a18

block: Add support for throttling burst max in QMP and the command line.

The max parameter of the leaky bucket throttling algorithm can be used to
allow the guest to do bursts.
The max value is a pool of I/O that the guest can use without being throttled
at all. Throttling is triggered once this pool is empty.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

blockdev.c

diff --git a/blockdev.c b/blockdev.c
index 5f5ba96..76e9308 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -494,13 +494,18 @@
     cfg.buckets[THROTTLE_OPS_WRITE].avg =
         qemu_opt_get_number(opts, "throttling.iops-write", 0);
 
-    cfg.buckets[THROTTLE_BPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_BPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_BPS_WRITE].max = 0;
-
-    cfg.buckets[THROTTLE_OPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_OPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_OPS_WRITE].max = 0;
+    cfg.buckets[THROTTLE_BPS_TOTAL].max =
+        qemu_opt_get_number(opts, "throttling.bps-total-max", 0);
+    cfg.buckets[THROTTLE_BPS_READ].max  =
+        qemu_opt_get_number(opts, "throttling.bps-read-max", 0);
+    cfg.buckets[THROTTLE_BPS_WRITE].max =
+        qemu_opt_get_number(opts, "throttling.bps-write-max", 0);
+    cfg.buckets[THROTTLE_OPS_TOTAL].max =
+        qemu_opt_get_number(opts, "throttling.iops-total-max", 0);
+    cfg.buckets[THROTTLE_OPS_READ].max =
+        qemu_opt_get_number(opts, "throttling.iops-read-max", 0);
+    cfg.buckets[THROTTLE_OPS_WRITE].max =
+        qemu_opt_get_number(opts, "throttling.iops-write-max", 0);
 
     cfg.op_size = 0;
 
@@ -761,6 +766,14 @@
     qemu_opt_rename(all_opts, "bps_rd", "throttling.bps-read");
     qemu_opt_rename(all_opts, "bps_wr", "throttling.bps-write");
 
+    qemu_opt_rename(all_opts, "iops_max", "throttling.iops-total-max");
+    qemu_opt_rename(all_opts, "iops_rd_max", "throttling.iops-read-max");
+    qemu_opt_rename(all_opts, "iops_wr_max", "throttling.iops-write-max");
+
+    qemu_opt_rename(all_opts, "bps_max", "throttling.bps-total-max");
+    qemu_opt_rename(all_opts, "bps_rd_max", "throttling.bps-read-max");
+    qemu_opt_rename(all_opts, "bps_wr_max", "throttling.bps-write-max");
+
     qemu_opt_rename(all_opts, "readonly", "read-only");
 
     value = qemu_opt_get(all_opts, "cache");
@@ -1245,8 +1258,22 @@
 
 /* throttling disk I/O limits */
 void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
-                               int64_t bps_wr, int64_t iops, int64_t iops_rd,
-                               int64_t iops_wr, Error **errp)
+                               int64_t bps_wr,
+                               int64_t iops,
+                               int64_t iops_rd,
+                               int64_t iops_wr,
+                               bool has_bps_max,
+                               int64_t bps_max,
+                               bool has_bps_rd_max,
+                               int64_t bps_rd_max,
+                               bool has_bps_wr_max,
+                               int64_t bps_wr_max,
+                               bool has_iops_max,
+                               int64_t iops_max,
+                               bool has_iops_rd_max,
+                               int64_t iops_rd_max,
+                               bool has_iops_wr_max,
+                               int64_t iops_wr_max, Error **errp)
 {
     ThrottleConfig cfg;
     BlockDriverState *bs;
@@ -1266,13 +1293,24 @@
     cfg.buckets[THROTTLE_OPS_READ].avg  = iops_rd;
     cfg.buckets[THROTTLE_OPS_WRITE].avg = iops_wr;
 
-    cfg.buckets[THROTTLE_BPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_BPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_BPS_WRITE].max = 0;
-
-    cfg.buckets[THROTTLE_OPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_OPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_OPS_WRITE].max = 0;
+    if (has_bps_max) {
+        cfg.buckets[THROTTLE_BPS_TOTAL].max = bps_max;
+    }
+    if (has_bps_rd_max) {
+        cfg.buckets[THROTTLE_BPS_READ].max = bps_rd_max;
+    }
+    if (has_bps_wr_max) {
+        cfg.buckets[THROTTLE_BPS_WRITE].max = bps_wr_max;
+    }
+    if (has_iops_max) {
+        cfg.buckets[THROTTLE_OPS_TOTAL].max = iops_max;
+    }
+    if (has_iops_rd_max) {
+        cfg.buckets[THROTTLE_OPS_READ].max = iops_rd_max;
+    }
+    if (has_iops_wr_max) {
+        cfg.buckets[THROTTLE_OPS_WRITE].max = iops_wr_max;
+    }
 
     cfg.op_size = 0;
 
@@ -1976,6 +2014,30 @@
             .type = QEMU_OPT_NUMBER,
             .help = "limit write bytes per second",
         },{
+            .name = "throttling.iops-total-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "I/O operations burst",
+        },{
+            .name = "throttling.iops-read-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "I/O operations read burst",
+        },{
+            .name = "throttling.iops-write-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "I/O operations write burst",
+        },{
+            .name = "throttling.bps-total-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "total bytes burst",
+        },{
+            .name = "throttling.bps-read-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "total bytes read burst",
+        },{
+            .name = "throttling.bps-write-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "total bytes write burst",
+        },{
             .name = "copy-on-read",
             .type = QEMU_OPT_BOOL,
             .help = "copy read data from backing file into image file",