| Message ID | 20211019202904.4857-1-mark.kanda@oracle.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Support fd-based KVM stats | expand |
On 19/10/21 22:29, Mark Kanda wrote: > This patchset adds QEMU support for querying fd-based KVM stats. The kernel > support is provided by: > > cb082bfab59a ("KVM: stats: Add fd-based API to read binary stats data") > > Patch 1 adds QMP support; patch 2 adds HMP support. Hi Mark, that's awesome, thanks! Just a couple remarks on the implementation: 1) for QMP, it would be nice to have separate commands for the schema and the value. This is because in the future we could consider passing the file descriptor directly to the QMP client; in which case, it would still be nicer to have QEMU turn the schema information into something more easily consumable. 2) for HMP, it would be nice to have the exponent converted to e.g. "nanoseconds" if the KvmStatUnit is seconds. It's not super important, but it would be nice. Something as simple as if (kvm_stat->unit == KVM_STAT_UNIT_SECONDS && kvm_stat->exponent >= -9 && kvm_stat->exponent <= 0 && kvm_stat->exponent % 3 == 0 && kvm_stat->base == 10) { const char *si_prefix[] = { "", "milli", "micro", "nano" }; monitor_printf(" %lu %sseconds", val->value, si_prefix[kvm_stat->exponent / -3]); } else ... (Yes, this is nitpicking; but in practice nanoseconds are the only case where currently the exponent is not 0, so...). 3) more recent versions of Linux also support histograms, for which you have to include the bucket size and the kind (logarithmic/linear) in QMP. For HMP it would be nice to have it printed as halt_wait_hist: [1 nanosecond]=200 [2]=30 [4]=50 [8]=120 but, for the first version, it's also okay if the QMP commands just skips unknown KVM_STATS_TYPE values altogether. Paolo > Mark Kanda (2): > qmp: Support fd-based KVM stats query > hmp: Support fd-based KVM stats query > > accel/kvm/kvm-all.c | 246 ++++++++++++++++++++++++++++++++++++++++++ > hmp-commands-info.hx | 13 +++ > include/monitor/hmp.h | 1 + > monitor/hmp-cmds.c | 52 +++++++++ > qapi/misc.json | 73 +++++++++++++ > 5 files changed, 385 insertions(+) >
This patchset adds QEMU support for querying fd-based KVM stats. The kernel support is provided by: cb082bfab59a ("KVM: stats: Add fd-based API to read binary stats data") Patch 1 adds QMP support; patch 2 adds HMP support. Mark Kanda (2): qmp: Support fd-based KVM stats query hmp: Support fd-based KVM stats query accel/kvm/kvm-all.c | 246 ++++++++++++++++++++++++++++++++++++++++++ hmp-commands-info.hx | 13 +++ include/monitor/hmp.h | 1 + monitor/hmp-cmds.c | 52 +++++++++ qapi/misc.json | 73 +++++++++++++ 5 files changed, 385 insertions(+)