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[82.30.61.225]) by smtp.gmail.com with ESMTPSA id b6-20020a05600c4e0600b003a5f4fccd4asm3840520wmq.35.2022.08.15.05.00.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Aug 2022 05:00:19 -0700 (PDT) Date: Mon, 15 Aug 2022 13:00:17 +0100 From: "Dr. David Alan Gilbert" To: zhenwei pi Cc: armbru@redhat.com, qemu-devel@nongnu.org, darren.kenny@oracle.com Subject: Re: [PATCH v4 1/1] monitor: Support specified vCPU registers Message-ID: References: <20220802073720.1236988-1-pizhenwei@bytedance.com> <20220802073720.1236988-2-pizhenwei@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220802073720.1236988-2-pizhenwei@bytedance.com> User-Agent: Mutt/2.2.6 (2022-06-05) Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * 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 > Reviewed-by: Markus Armbruster > Signed-off-by: zhenwei pi Reviewed-by: Dr. David Alan Gilbert > --- > 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 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK