Re: [libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling?for -blockdev
On Mon, Oct 16, 2023 at 14:19:08 +, Chun Feng Wu wrote: > Thanks for your info! Currently, the iotune in libvirt’s xml indeed works > well, BTW, is there any plan for such “re-engineering”? No, there are no plans, as the current approach covers the vast majority of use cases. Spending significant engineering resources on something which will not get much use is not in the interest of the comunity.
RE: [libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling for -blockdev
Thanks for your info! Currently, the iotune in libvirt’s xml indeed works well, BTW, is there any plan for such “re-engineering”? From: Peter Krempa Date: Monday, October 16, 2023 at 21:53 To: Chun Feng Wu Cc: libvir-list@redhat.com Subject: [EXTERNAL] Re: [libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling for -blockdev On Mon, Oct 16, 2023 at 13:36:42 +, Chun Feng Wu wrote: > Does this libvirt throttling support “chained throttle filters” for single > disk described in QEMU doc: > https://github.com/qemu/qemu/blob/master/docs/throttle.txt (“The 'throttle' > block filter”) No, libvirt currently still uses the older approach by using 'block_set_io_throttle' QMP command. This was used at the beginning because the 'throttle' layer was not yet ready at the point when libvirt adopted -blockdev. It is sufficient for the throttling options that are currently configurable via libvirt's XML. Note that to use the full potential of the throttle groups and hierarchical throttling will require significant re-engineering of the XML configuration of throttling.
Re: [libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling for -blockdev
On Mon, Oct 16, 2023 at 13:36:42 +, Chun Feng Wu wrote: > Does this libvirt throttling support “chained throttle filters” for single > disk described in QEMU doc: > https://github.com/qemu/qemu/blob/master/docs/throttle.txt (“The 'throttle' > block filter”) No, libvirt currently still uses the older approach by using 'block_set_io_throttle' QMP command. This was used at the beginning because the 'throttle' layer was not yet ready at the point when libvirt adopted -blockdev. It is sufficient for the throttling options that are currently configurable via libvirt's XML. Note that to use the full potential of the throttle groups and hierarchical throttling will require significant re-engineering of the XML configuration of throttling.
[libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling for -blockdev
Does this libvirt throttling support “chained throttle filters” for single disk described in QEMU doc: https://github.com/qemu/qemu/blob/master/docs/throttle.txt (“The 'throttle' block filter”)
Re: [libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling for -blockdev
On Mon, Aug 13, 2018 at 06:00:11PM +0200, Peter Krempa wrote: The proper way to do this would be to use the 'throttle' driver but unfortunately it can't change the 'throttle_group' so we can't provide feature parity. This hack uses the block_set_io_throttle command to do so until we can properly replace it. Signed-off-by: Peter Krempa --- src/qemu/qemu_process.c | 50 + 1 file changed, 50 insertions(+) Reviewed-by: Ján Tomko Jano signature.asc Description: Digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[libvirt] [PATCHv2 37/62] qemu: process: Setup disk io throttling for -blockdev
The proper way to do this would be to use the 'throttle' driver but
unfortunately it can't change the 'throttle_group' so we can't provide
feature parity. This hack uses the block_set_io_throttle command to do
so until we can properly replace it.
Signed-off-by: Peter Krempa
---
src/qemu/qemu_process.c | 50 +
1 file changed, 50 insertions(+)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 0bf8245173..3495733041 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -6230,6 +6230,53 @@ qemuProcessGenID(virDomainObjPtr vm,
}
+/**
+ * qemuProcessSetupDiskThrottlingBlockdev:
+ *
+ * Sets up disk trottling for -blockdev via block_set_io_throttle monitor
+ * command. This hack should be replaced by proper use of the 'throttle'
+ * blockdev driver in qemu once it will support changing of the throttle group.
+ */
+static int
+qemuProcessSetupDiskThrottlingBlockdev(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ qemuDomainAsyncJob asyncJob)
+{
+qemuDomainObjPrivatePtr priv = vm->privateData;
+size_t i;
+int ret = -1;
+
+if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV))
+return 0;
+
+VIR_DEBUG("Setting up disk throttling for -blockdev via
block_set_io_throttle");
+
+if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
+return -1;
+
+for (i = 0; i < vm->def->ndisks; i++) {
+virDomainDiskDefPtr disk = vm->def->disks[i];
+qemuDomainDiskPrivatePtr diskPriv = QEMU_DOMAIN_DISK_PRIVATE(disk);
+
+if (!qemuDiskConfigBlkdeviotuneEnabled(disk))
+continue;
+
+if (qemuMonitorSetBlockIoThrottle(qemuDomainGetMonitor(vm), NULL,
+ diskPriv->backendQomName,
+ >blkdeviotune,
+ true, true, true) < 0)
+goto cleanup;
+}
+
+ret = 0;
+
+ cleanup:
+if (qemuDomainObjExitMonitor(driver, vm) < 0)
+ret = -1;
+return ret;
+}
+
+
/**
* qemuProcessLaunch:
*
@@ -6548,6 +6595,9 @@ qemuProcessLaunch(virConnectPtr conn,
if (qemuProcessSetupBalloon(driver, vm, asyncJob) < 0)
goto cleanup;
+if (qemuProcessSetupDiskThrottlingBlockdev(driver, vm, asyncJob) < 0)
+goto cleanup;
+
/* Since CPUs were not started yet, the balloon could not return the memory
* to the host and thus cur_balloon needs to be updated so that GetXMLdesc
* and friends return the correct size in case they can't grab the job */
--
2.16.2
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