From: Jim Fehlig <jfehlig@novell.com>
Date: Fri, 26 Aug 2011 18:10:26 +0000 (-0600)
Subject: Set qemu migration speed unlimited when migrating to file
X-Git-Tag: v0.9.5-rc3~27
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ef1065cf5ac;p=thirdparty%2Flibvirt.git

Set qemu migration speed unlimited when migrating to file

The qemu migration speed default is 32MiB/s as defined in migration.c

/* Migration speed throttling */
static int64_t max_throttle = (32 << 20);

There's no need to throttle migration when targeting a file, so set migration
speed to unlimited prior to migration, and restore to libvirt default value
after migration.

Default units is MB for migrate_set_speed monitor command, so
(INT64_MAX / (1024 * 1024)) is used for unlimited migration speed.

Tested with both json and text monitors.
---

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 7fd4192f6e..b882d06cdc 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2718,6 +2718,16 @@ qemuMigrationToFile(struct qemud_driver *driver, virDomainObjPtr vm,
     bool restoreLabel = false;
     virCommandPtr cmd = NULL;
     int pipeFD[2] = { -1, -1 };
+    unsigned long saveMigBandwidth = priv->migMaxBandwidth;
+
+    /* Increase migration bandwidth to unlimited since target is a file.
+     * Failure to change migration speed is not fatal. */
+    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) == 0) {
+        qemuMonitorSetMigrationSpeed(priv->mon,
+                                     QEMU_DOMAIN_FILE_MIG_BANDWIDTH_MAX);
+        priv->migMaxBandwidth = QEMU_DOMAIN_FILE_MIG_BANDWIDTH_MAX;
+        qemuDomainObjExitMonitorWithDriver(driver, vm);
+    }
 
     if (qemuCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATE_QEMU_FD) &&
         (!compressor || pipe(pipeFD) == 0)) {
@@ -2829,6 +2839,13 @@ qemuMigrationToFile(struct qemud_driver *driver, virDomainObjPtr vm,
     ret = 0;
 
 cleanup:
+    /* Restore max migration bandwidth */
+    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) == 0) {
+        qemuMonitorSetMigrationSpeed(priv->mon, saveMigBandwidth);
+        priv->migMaxBandwidth = saveMigBandwidth;
+        qemuDomainObjExitMonitorWithDriver(driver, vm);
+    }
+
     VIR_FORCE_CLOSE(pipeFD[0]);
     VIR_FORCE_CLOSE(pipeFD[1]);
     virCommandFree(cmd);