PING: Re: [PATCH v4 1/1] monitor: Support specified vCPU registers

[zhenwei pi]

PING!

On 8/15/22 20:00, Dr. David Alan Gilbert wrote:
> * zhenwei pi (pizhenwei@bytedance.com) wrote:
> > Originally we have to get all the vCPU registers and parse the
> > specified one. To improve the performance of this usage, allow user
> > specified vCPU id to query registers.
> >
> > Run a VM with 16 vCPU, use bcc tool to track the latency of
> > 'hmp_info_registers':
> > 'info registers -a' uses about 3ms;
> > 'info registers 12' uses about 150us.
> >
> > Cc: Darren Kenny <darren.kenny@oracle.com>
> > Reviewed-by: Markus Armbruster <armbru@redhat.com>
> > Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>
> > ---
> >   hmp-commands-info.hx |  8 +++++---
> >   monitor/misc.c       | 10 ++++++++--
> >   2 files changed, 13 insertions(+), 5 deletions(-)
> >
> > diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> > index 188d9ece3b..e012035541 100644
> > --- a/hmp-commands-info.hx
> > +++ b/hmp-commands-info.hx
> > @@ -100,9 +100,11 @@ ERST
> >   
> >       {
> >           .name       = "registers",
> > -        .args_type  = "cpustate_all:-a",
> > -        .params     = "[-a]",
> > -        .help       = "show the cpu registers (-a: all - show register info for all 
> > cpus)",
> > +        .args_type  = "cpustate_all:-a,vcpu:i?",
> > +        .params     = "[-a|vcpu]",
> > +        .help       = "show the cpu registers (-a: show register info for all 
> > cpus;"
> > +                      " vcpu: specific vCPU to query; show the current CPU's 
> > registers if"
> > +                      " no argument is specified)",
> >           .cmd        = hmp_info_registers,
> >       },
> >   
> > diff --git a/monitor/misc.c b/monitor/misc.c
> > index 3d2312ba8d..6436a8786b 100644
> > --- a/monitor/misc.c
> > +++ b/monitor/misc.c
> > @@ -307,6 +307,7 @@ int monitor_get_cpu_index(Monitor *mon)
> >   static void hmp_info_registers(Monitor *mon, const QDict *qdict)
> >   {
> >       bool all_cpus = qdict_get_try_bool(qdict, "cpustate_all", false);
> > +    int vcpu = qdict_get_try_int(qdict, "vcpu", -1);
> >       CPUState *cs;
> >   
> >       if (all_cpus) {
> > @@ -315,13 +316,18 @@ static void hmp_info_registers(Monitor *mon, const QDict 
> > *qdict)
> >               cpu_dump_state(cs, NULL, CPU_DUMP_FPU);
> >           }
> >       } else {
> > -        cs = mon_get_cpu(mon);
> > +        cs = vcpu >= 0 ? qemu_get_cpu(vcpu) : mon_get_cpu(mon);
> >   
> >           if (!cs) {
> > -            monitor_printf(mon, "No CPU available\n");
> > +            if (vcpu >= 0) {
> > +                monitor_printf(mon, "CPU#%d not available\n", vcpu);
> > +            } else {
> > +                monitor_printf(mon, "No CPU available\n");
> > +            }
> >               return;
> >           }
> >   
> > +        monitor_printf(mon, "\nCPU#%d\n", cs->cpu_index);
> >           cpu_dump_state(cs, NULL, CPU_DUMP_FPU);
> >       }
> >   }
> > --
> > 2.20.1

--
zhenwei pi