Re: [libvirt] [PATCH 2/4] qemu: Add support for iothreads

On Mon, Aug 25, 2014 at 08:38:07PM -0400, John Ferlan wrote: > Add a new capability to ensure the iothreads feature exists for the qemu > emulator being run - requires the "query-iothreads" QMP command. Using the > domain XML add correspoding command argument in order to generate the > threads. The iothreads will use a name space "libvirtIothread#" where, the > future patch to add support for using an iothread to a disk definition to > merely define which of the available threads to use. > > Add tests to ensure the xml/argv processing is correct. Note that no > change was made to qemuargv2xmltest.c as processing the -object element > would require knowing more than just iothreads. > > Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; > --- > src/qemu/qemu_capabilities.c | 2 ++ > src/qemu/qemu_capabilities.h | 1 + > src/qemu/qemu_command.c | 13 ++++++++++ > tests/qemuxml2argvdata/qemuxml2argv-iothreads.args | 8 ++++++ > tests/qemuxml2argvdata/qemuxml2argv-iothreads.xml | 29 ++++++++++++++++++++++ > tests/qemuxml2argvtest.c | 2 ++ > tests/qemuxml2xmltest.c | 1 + > 7 files changed, 56 insertions(+) > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-iothreads.args > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-iothreads.xml > > diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c > index 410086b..b331be7 100644 > --- a/src/qemu/qemu_capabilities.c > +++ b/src/qemu/qemu_capabilities.c > @@ -268,6 +268,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST, > "rtc-reset-reinjection", > > "splash-timeout", /* 175 */ > + "query-iothreads", Why "query-" when the capability is _OBJECT_? Or is this just a typo? </bikeshed>

> ); > > > @@ -1430,6 +1431,7 @@ struct virQEMUCapsStringFlags virQEMUCapsCommands[] = { > { "nbd-server-start", QEMU_CAPS_NBD_SERVER }, > { "change-backing-file", QEMU_CAPS_CHANGE_BACKING_FILE }, > { "rtc-reset-reinjection", QEMU_CAPS_RTC_RESET_REINJECTION }, > + { "query-iothreads", QEMU_CAPS_OBJECT_IOTHREAD}, We have virQEMUCapsObjectTypes[] where you can just stick the name of the object you want to test, and not rely on a related command to probe for it.

> }; > > struct virQEMUCapsStringFlags virQEMUCapsEvents[] = { > diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h > index 48a4eaa..0980c00 100644 > --- a/src/qemu/qemu_capabilities.h > +++ b/src/qemu/qemu_capabilities.h > @@ -215,6 +215,7 @@ typedef enum { > QEMU_CAPS_OBJECT_USB_AUDIO = 173, /* usb-audio device support */ > QEMU_CAPS_RTC_RESET_REINJECTION = 174, /* rtc-reset-reinjection monitor command */ > QEMU_CAPS_SPLASH_TIMEOUT = 175, /* -boot splash-time */ > + QEMU_CAPS_OBJECT_IOTHREAD = 176, /* -object iothread */ > > QEMU_CAPS_LAST, /* this must always be the last item */ > } virQEMUCapsFlags; > diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c > index 6dac9d3..287a3f3 100644 > --- a/src/qemu/qemu_command.c > +++ b/src/qemu/qemu_command.c > @@ -7510,6 +7510,19 @@ qemuBuildCommandLine(virConnectPtr conn, > virCommandAddArg(cmd, smp); > VIR_FREE(smp); > > + if (def->iothreads > 0 && > + virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_IOTHREAD)) { > + /* Create named iothread objects starting with 1. These may be used > + * by a disk definition which will associate to an iothread by > + * supplying a value of 1 up to the number of iothreads available > + * (since 0 would indicate to not use the feature). > + */ > + for (i = 1; i <= def->iothreads; i++) { > + virCommandAddArg(cmd, "-object"); > + virCommandAddArgFormat(cmd, "iothread,id=libvirtIothread%zu", i); I don't see we would use 'libvirt*' naming for any other IDs, 'iothread%zu' would be enough, I guess (and the command-line wouldn't be so long as well).