| Message ID | 20220727005123.1093478-2-pizhenwei@bytedance.com |
|---|---|
| State | New |
| Headers | show |
| Series | monitor: Support specified vCPU registers | expand |
zhenwei pi <pizhenwei@bytedance.com> writes: > 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> > Signed-off-by: zhenwei pi <pizhenwei@bytedance.com> > --- > hmp-commands-info.hx | 7 ++++--- > monitor/misc.c | 18 ++++++++++++++++++ > 2 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx > index 3ffa24bd67..7a00b4ded3 100644 > --- a/hmp-commands-info.hx > +++ b/hmp-commands-info.hx > @@ -100,9 +100,10 @@ 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: all - show register info for all cpus;" > + " vcpu: specific vCPU to query)", Recommend to document explicitly that it shows the current CPU's registers when no argument is specified. > .cmd = hmp_info_registers, > }, > > diff --git a/monitor/misc.c b/monitor/misc.c > index 3d2312ba8d..8e1d4840f2 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) { > @@ -314,6 +315,23 @@ static void hmp_info_registers(Monitor *mon, const QDict *qdict) > monitor_printf(mon, "\nCPU#%d\n", cs->cpu_index); > cpu_dump_state(cs, NULL, CPU_DUMP_FPU); > } > + } else if (vcpu >= 0) { > + CPUState *target_cs = NULL; > + > + CPU_FOREACH(cs) { > + if (cs->cpu_index == vcpu) { > + target_cs = cs; > + break; > + } > + } Please use qemu_get_cpu(). > + > + if (!target_cs) { > + monitor_printf(mon, "CPU#%d not available\n", vcpu); > + return; > + } > + > + monitor_printf(mon, "\nCPU#%d\n", target_cs->cpu_index); > + cpu_dump_state(target_cs, NULL, CPU_DUMP_FPU); We show the CPU number when the user asked for this number, but ... > } else { > cs = mon_get_cpu(mon); if (!cs) { monitor_printf(mon, "No CPU available\n"); return; } cpu_dump_state(cs, NULL, CPU_DUMP_FPU); ... we don't show it when the user asked for the current CPU. It's arguably more relevant then. } } Suggest something like } else { cs = vcpu >= 0 ? qemu_get_cpu(vcpu) : mon_get_cpu(mon); if (!cs) { monitor_printf(mon, "CPU#%d not available\n", vcpu); return; } monitor_printf(mon, "\nCPU#%d\n", cs->cpu_index); cpu_dump_state(cs, NULL, CPU_DUMP_FPU); }
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx index 3ffa24bd67..7a00b4ded3 100644 --- a/hmp-commands-info.hx +++ b/hmp-commands-info.hx @@ -100,9 +100,10 @@ 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: all - show register info for all cpus;" + " vcpu: specific vCPU to query)", .cmd = hmp_info_registers, }, diff --git a/monitor/misc.c b/monitor/misc.c index 3d2312ba8d..8e1d4840f2 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) { @@ -314,6 +315,23 @@ static void hmp_info_registers(Monitor *mon, const QDict *qdict) monitor_printf(mon, "\nCPU#%d\n", cs->cpu_index); cpu_dump_state(cs, NULL, CPU_DUMP_FPU); } + } else if (vcpu >= 0) { + CPUState *target_cs = NULL; + + CPU_FOREACH(cs) { + if (cs->cpu_index == vcpu) { + target_cs = cs; + break; + } + } + + if (!target_cs) { + monitor_printf(mon, "CPU#%d not available\n", vcpu); + return; + } + + monitor_printf(mon, "\nCPU#%d\n", target_cs->cpu_index); + cpu_dump_state(target_cs, NULL, CPU_DUMP_FPU); } else { cs = mon_get_cpu(mon);
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> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com> --- hmp-commands-info.hx | 7 ++++--- monitor/misc.c | 18 ++++++++++++++++++ 2 files changed, 22 insertions(+), 3 deletions(-)