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

[zhenwei pi <pizhenwei@bytedance.com>]

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