Re: [libvirt] [REPOST PATCH v2 05/12] lib: Introduce virDomainSetIOThreadParams

Create a new API that will allow an adjustment of IOThread polling parameters for the specified IOThread. These parameters will not be saved in the guest XML. Currently the only parameters supported will allow the hypervisor to adjust the parameters used to limit and alter the scope of the polling interval. The polling interval allows the IOThread to spend more or less time processing in the guest. Based on code originally posted by Pavel Hrdina <phrdina(a)redhat.com&gt; to add virDomainAddIOThreadParams and virDomainModIOThreadParams. Modification of those changes to use virDomainSetIOThreadParams instead and remove concepts related to saving the data in guest XML as well as the way to specifically enable the polling parameters. Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; ACKed-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- include/libvirt/libvirt-domain.h | 44 ++++++++++++++++++++ src/driver-hypervisor.h | 8 ++++ src/libvirt-domain.c | 70 ++++++++++++++++++++++++++++++++ src/libvirt_public.syms | 5 +++ src/remote/remote_driver.c | 1 + src/remote/remote_protocol.x | 21 +++++++++- src/remote_protocol-structs | 10 +++++ 7 files changed, 158 insertions(+), 1 deletion(-) diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h index 58fd4bc10c..bf89d0149f 100644 --- a/include/libvirt/libvirt-domain.h +++ b/include/libvirt/libvirt-domain.h @@ -1911,6 +1911,50 @@ int virDomainDelIOThread(virDomainPtr domain, unsigned int iothread_id, unsigned int flags); +/* IOThread set parameters */ + +/** + * VIR_DOMAIN_IOTHREAD_POLL_MAX_NS: + * + * The maximum polling time that can be used by polling algorithm in ns. + * The polling time starts at 0 (zero) and is the time spent by the guest + * to process IOThread data before returning the CPU to the host. The + * polling time will be dynamically modified over time based on the + * poll_grow and poll_shrink parameters provided. A value set too large + * will cause more CPU time to be allocated the guest. A value set too + * small will not provide enough cycles for the guest to process data. + * The polling interval is not available for statistical purposes. + */ +# define VIR_DOMAIN_IOTHREAD_POLL_MAX_NS "poll_max_ns" + +/** + * VIR_DOMAIN_IOTHREAD_POLL_GROW: + * + * This provides a value for the dynamic polling adjustment algorithm to + * use to grow its polling interval up to the poll_max_ns value. A value + * of 0 (zero) allows the hypervisor to choose its own value. The algorithm + * to use for adjustment is hypervisor specific. + */ +# define VIR_DOMAIN_IOTHREAD_POLL_GROW "poll_grow" + +/** + * VIR_DOMAIN_IOTHREAD_POLL_SHRINK: + * + * This provides a value for the dynamic polling adjustment algorithm to + * use to shrink its polling interval when the polling interval exceeds + * the poll_max_ns value. A value of 0 (zero) allows the hypervisor to + * choose its own value. The algorithm to use for adjustment is hypervisor + * specific. + */ +# define VIR_DOMAIN_IOTHREAD_POLL_SHRINK "poll_shrink" + +int virDomainSetIOThreadParams(virDomainPtr domain,

+ unsigned int iothread_id, + virTypedParameterPtr params, + int nparams, + unsigned int flags);