From: zhenwei pi <pizhen...@bytedance.com>
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.ke...@oracle.com>
Reviewed-by: Markus Armbruster <arm...@redhat.com>
Signed-off-by: zhenwei pi <pizhen...@bytedance.com>
Reviewed-by: Darren Kenny <darren.ke...@oracle.com>
Message-Id: <20220802073720.1236988-2-pizhen...@bytedance.com>
Signed-off-by: Dr. David Alan Gilbert <dgilb...@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);
}
}
--
2.37.3
