Re: [PATCH V1 0/6] fast qom tree get

Steven Sistare <steven.sistare(a)oracle.com&gt; writes: > On 4/28/2025 4:04 AM, Markus Armbruster wrote: >> Steven Sistare <steven.sistare(a)oracle.com&gt; writes: >> >>> On 4/9/2025 3:39 AM, Markus Armbruster wrote: >>>> Hi Steve, I apologize for the slow response. >>>> >>>> Steve Sistare <steven.sistare(a)oracle.com&gt; writes: >>>> >>>>> Using qom-list and qom-get to get all the nodes and property values in a >>>>> QOM tree can take multiple seconds because it requires 1000's of individual >>>>> QOM requests. Some managers fetch the entire tree or a large subset >>>>> of it when starting a new VM, and this cost is a substantial fraction of >>>>> start up time. >>>> >>>> "Some managers"... could you name one? >>> >>> My personal experience is with Oracle's OCI, but likely others could benefit. >> >> Elsewhere in this thread, we examined libvirt's use qom-get. Its use of >> qom-get is also noticably slow, and your work could speed it up. >> However, most of its use is for working around QMP interface >> shortcomings around probing CPU flags. Addressing these would help it >> even more. >> >> This makes me wonder what questions Oracle's OCI answers with the help >> of qom-get. Can you briefly describe them? >> >> Even if OCI would likewise be helped more by better QMP queries, your >> fast qom tree get work might still be useful. > > We already optimized our queries as a first step, but what remains is still > significant, which is why I submitted this RFE. I understand your motivation. I'd like to learn more on what OCI actually needs from QMP, to be able to better serve it and potentially other management applications.