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
