[libvirt] [PATCH V2] Set qemu migration speed unlimited when migrating to file

Discussed previously: https://www.redhat.com/archives/libvir-list/2011-August/msg00166.html The qemu migration speed default is 32MiB/s as defined in migration.c /* Migration speed throttling */ static int64_t max_throttle = (32 << 20); There is no reason to throttle migration when targeting a file. For dump and save operations, set migration speed to unlimited prior to migration and restore to 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. V2: - Use qemuDomainObjEnterMonitorAsync() instead of qemuDomainObjEnterMonitor() - Check return status of qemuDomainObjEnterMonitorAsync() --- src/qemu/qemu_migration.c | 14 ++++++++++++++ 1 files changed, 14 insertions(+), 0 deletions(-) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index 7aeea69..fa05ccf 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -2676,6 +2676,14 @@ qemuMigrationToFile(struct qemud_driver *driver, virDomainObjPtr vm, virCommandPtr cmd = NULL; int pipeFD[2] = { -1, -1 }; + /* No need for qemu default of 32MiB/s when migrating to a file. + Default speed unit is MB, so set to unlimited with INT64_MAX / 1M. + Failure to change migration speed is not fatal. */ + if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) == 0) { + qemuMonitorSetMigrationSpeed(priv->mon, INT64_MAX / (1024 * 1024)); + qemuDomainObjExitMonitorWithDriver(driver, vm); + } + if (qemuCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATE_QEMU_FD) && (!compressor || pipe(pipeFD) == 0)) { /* All right! We can use fd migration, which means that qemu @@ -2783,6 +2791,12 @@ qemuMigrationToFile(struct qemud_driver *driver, virDomainObjPtr vm, ret = 0; cleanup: + /* Restore migration speed to 32MiB/s default */ + if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) == 0) { + qemuMonitorSetMigrationSpeed(priv->mon, (32 << 20)); + qemuDomainObjExitMonitorWithDriver(driver, vm); + } + VIR_FORCE_CLOSE(pipeFD[0]); VIR_FORCE_CLOSE(pipeFD[1]); virCommandFree(cmd); -- 1.7.5.4