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 register 12' uses about 150us. Signed-off-by: zhenwei pi <pizhen...@bytedance.com> --- hmp-commands-info.hx | 6 +++--- monitor/misc.c | 19 +++++++++++++++++++ 2 files changed, 22 insertions(+), 3 deletions(-) diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx index 3ffa24bd67..6023e2b5c5 100644 --- a/hmp-commands-info.hx +++ b/hmp-commands-info.hx @@ -100,9 +100,9 @@ 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: vCPU to query)", .cmd = hmp_info_registers, }, diff --git a/monitor/misc.c b/monitor/misc.c index 3d2312ba8d..b12309faad 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 +315,24 @@ 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); + return; } else { cs = mon_get_cpu(mon); -- 2.20.1