Re: [libvirt] [PATCH RFC 1/7] libxl: implement virDomainGetCPUStats

17 Sep 2015

On 09/17/2015 04:09 AM, Jim Fehlig wrote:
...
On 09/08/2015 02:27 AM, Joao Martins wrote:
...
Introduce support for domainGetCPUStats API call and consequently
allow us to use `virsh cpu-stats`. The latter returns a more brief
output than the one provided by`virsh vcpuinfo`.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
  src/libxl/libxl_driver.c | 111 +++++++++++++++++++++++++++++++++++++++++++++++
  1 file changed, 111 insertions(+)

diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 5f69b49..101e4c7 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -73,6 +73,8 @@ VIR_LOG_INIT("libxl.libxl_driver");
  #define LIBXL_CONFIG_FORMAT_XM "xen-xm"
  #define LIBXL_CONFIG_FORMAT_SEXPR "xen-sxpr"
+#define LIBXL_NB_TOTAL_CPU_STAT_PARAM 1
+
  #define HYPERVISOR_CAPABILITIES "/proc/xen/capabilities"
  #define HYPERVISOR_XENSTORED "/dev/xen/xenstored"
@@ -4638,6 +4640,114 @@ libxlDomainIsUpdated(virDomainPtr dom)
  }
static int
+libxlDomainGetTotalCPUStats(libxlDriverPrivatePtr driver,
+                            virDomainObjPtr vm,
+                            virTypedParameterPtr params,
+                            unsigned int nparams)
+{
+    libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver);
+    libxl_dominfo d_info;
+    int ret = -1;
+
+    if (nparams == 0)
+        return LIBXL_NB_TOTAL_CPU_STAT_PARAM;
+
+    if (libxl_domain_info(cfg->ctx, &d_info, vm->def->id) != 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("libxl_domain_info failed for domain '%d'"),
+                       vm->def->id);
+        return ret;
+    }
+
I see that xl calls libxl_dominfo_dispose() after successful 
libxl_domain_info(). We might be missing that elsewhere in the libxl driver.
You're right. And I don't do that in all of the other patches of this series
that use libxl_domain_info. Tracking down these calls only libxlReconnectDomain
and libxlDomainGetInfo are missing the dispose. I will send a patch for these two.
...
...
+    if (virTypedParameterAssign(¶ms[0], VIR_DOMAIN_CPU_STATS_CPUTIME,
+                                VIR_TYPED_PARAM_ULLONG, d_info.cpu_time) < 0)
+        return ret;
+
+    return nparams;
+}
+
+static int
+libxlDomainGetPerCPUStats(libxlDriverPrivatePtr driver,
+                            virDomainObjPtr vm,
+                            virTypedParameterPtr params,
+                            unsigned int nparams,
+                            int start_cpu,
+                            unsigned int ncpus)
Indentation of parameters is off.
This one slipped slipped me, will fix that. I ran make syntax-check again and
there is one two other tiny issue regarding BlockStats macros, so I am including
those in v2.
...
...
+{
+    libxl_vcpuinfo *vcpuinfo;
+    int maxcpu, hostcpus;
+    size_t i;
+    libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver);
+    int ret = -1;
+
+    if (nparams == 0 && ncpus != 0)
+        return LIBXL_NB_TOTAL_CPU_STAT_PARAM;
+    else if (nparams == 0)
+        return vm->def->maxvcpus;
+
+    if ((vcpuinfo = libxl_list_vcpu(cfg->ctx, vm->def->id, &maxcpu,
+                                    &hostcpus)) == NULL) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Failed to list vcpus for domain '%d' with libxenlight"),
+                       vm->def->id);
+        goto cleanup;
+    }
+
+    for (i = start_cpu; i < maxcpu && i < ncpus; ++i) {
+        if (virTypedParameterAssign(¶ms[(i-start_cpu)],
+                                    VIR_DOMAIN_CPU_STATS_CPUTIME,
+                                    VIR_TYPED_PARAM_ULLONG,
+                                    vcpuinfo[i].vcpu_time) < 0)
+            goto cleanup;
+
+        libxl_vcpuinfo_dispose(&vcpuinfo[i]);
The call to libxl_vcpuinfo_dispose() can be removed
...
+    }
+    ret = nparams;
+
+ cleanup:
+    VIR_FREE(vcpuinfo);
if the VIR_FREE() is replaced with libxl_vcpuinfo_list_free().
Got it.
...
Other than the few nits, looks good.
BTW, thanks for the patches! But be warned: I may make slow progress reviewing them.
Regards,
Jim
...
+    return ret;
+}
+
+static int
+libxlDomainGetCPUStats(virDomainPtr dom,
+                       virTypedParameterPtr params,
+                       unsigned int nparams,
+                       int start_cpu,
+                       unsigned int ncpus,
+                       unsigned int flags)
+{
+    libxlDriverPrivatePtr driver = dom->conn->privateData;
+    virDomainObjPtr vm = NULL;
+    int ret = -1;
+
+    virCheckFlags(VIR_TYPED_PARAM_STRING_OKAY, -1);
+
+    if (!(vm = libxlDomObjFromDomain(dom)))
+        goto cleanup;
+
+    if (virDomainGetCPUStatsEnsureACL(dom->conn, vm->def) < 0)
+        goto cleanup;
+
+    if (!virDomainObjIsActive(vm)) {
+        virReportError(VIR_ERR_OPERATION_INVALID,
+                       "%s", _("domain is not running"));
+        goto cleanup;
+    }
+
+    if (start_cpu == -1)
+        ret = libxlDomainGetTotalCPUStats(driver, vm, params, nparams);
+    else
+        ret = libxlDomainGetPerCPUStats(driver, vm, params, nparams,
+                                          start_cpu, ncpus);
+
+ cleanup:
+    if (vm)
+        virObjectUnlock(vm);
+    return ret;
+}
+
+static int
  libxlConnectDomainEventRegisterAny(virConnectPtr conn, virDomainPtr dom, int eventID,
                                     virConnectDomainEventGenericCallback callback,
                                     void *opaque, virFreeCallback freecb)
@@ -5230,6 +5340,7 @@ static virHypervisorDriver libxlHypervisorDriver = {
  #endif
      .nodeGetFreeMemory = libxlNodeGetFreeMemory, /* 0.9.0 */
      .nodeGetCellsFreeMemory = libxlNodeGetCellsFreeMemory, /* 1.1.1 */
+    .domainGetCPUStats = libxlDomainGetCPUStats, /* 1.2.20 */
      .connectDomainEventRegister = libxlConnectDomainEventRegister, /* 0.9.0 */
      .connectDomainEventDeregister = libxlConnectDomainEventDeregister, /* 0.9.0 */
      .domainManagedSave = libxlDomainManagedSave, /* 0.9.2 */


    