Re: [libvirt] [PATCH v3 3/9] qemu: Implement the qemu driver fetch for IOThreads

On Tue, Feb 17, 2015 at 04:03:52PM -0500, John Ferlan wrote: > Depending on the flags passed, either attempt to return the active/live > IOThread data for the domain or the config data. > > The active/live path will call into the Monitor in order to get the > IOThread data and then correlate the thread_id's returned from the > monitor to the currently running system/threads in order to ascertain > the affinity for each iothread_id. > > The config path will map each of the configured IOThreads and return > any configured iothreadspin data > > Both paths will peruse the 'targetDef' domain list looking for 'disks' > that have been assigned to a specific IOThread. An IOThread may have > no resources associated > > Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; > --- > src/qemu/qemu_driver.c | 281 +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 281 insertions(+) > Just a few nits, until the API gets final... > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > index 1bbbe9b..2c9d08c 100644 > +static int > + > + if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0) > + goto cleanup; > + > + if (!virDomainObjIsActive(vm)) { > + virReportError(VIR_ERR_OPERATION_INVALID, "%s", > + _("cannot list IOThreads for an inactive domain")); > + goto endjob; > + } > + > + priv = vm->privateData; > + if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_OBJECT_IOTHREAD)) { > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", > + _("IOThreads not supported with this binary")); > + goto endjob; > + } > + > + if (qemuDomainObjEnterMonitorAsync(driver, vm, QEMU_ASYNC_JOB_NONE) < 0) > + goto endjob; EnterMonitorAsync with ASYNC_JOB_NONE is essentially EnterMonitor > + for (i = 0; i < targetDef->iothreads; i++) { > + if (VIR_ALLOC(info_ret[i]) < 0) > + goto cleanup; > + > + /* IOThreads being counting at 1 */ > + info_ret[i]->iothread_id = i + 1; > + > + if (VIR_ALLOC_N(info_ret[i]->cpumap, maplen) < 0) > + goto cleanup; > + > + /* Initialize the cpumap */ > + info_ret[i]->cpumaplen = maplen; > + memset(info_ret[i]->cpumap, 0xff, maplen); > + if (maxcpu % 8) > + info_ret[i]->cpumap[maplen - 1] &= (1 << maxcpu % 8) - 1; virBitmapToData could make this more readable.

> + } > + > + /* If iothreadspin setting exists, there are unused physical cpus */ > + iothreadspin_list = targetDef->cputune.iothreadspin; A temporary variable pointing to iothreadspin[i] is more common.

> + for (i = 0; i < targetDef->cputune.niothreadspin; i++) { > + /* vcpuid is the iothread_id... > + * iothread_id is the index into info_ret + 1, so we can > + * assume that the info_ret index we want is vcpuid - 1 > + */ > + cpumap = info_ret[iothreadspin_list[i]->vcpuid - 1]->cpumap; > + cpumask = iothreadspin_list[i]->cpumask; > + > + for (pcpu = 0; pcpu < maxcpu; pcpu++) { > + if (virBitmapGetBit(cpumask, pcpu, &pinned) < 0) > + goto cleanup; > + if (!pinned) > + VIR_UNUSE_CPU(cpumap, pcpu); > + } > + } > +