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

[Dr. David Alan Gilbert]

* zhenwei pi (pizhenwei@bytedance.com) wrote:
> PING!

It's OK, I've got it lined up for a pull I'll do in a few days time.

Dave

> 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
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK