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Adds support to param 'vcpu_time' in qemu_driver.

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This involves setting the cpuacct cgroup to a per-vcpu granularity,
as well as summing the each vcpu accounting into a common array.
Now that we are reading more than one cgroup file, we double-check
that cpus weren't hot-plugged between reads to invalidate our
summing.

Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Hu Tao 2012-05-09 16:41:38 +08:00 committed by Eric Blake
parent d29a7aaa1a
commit fe0aac0503
2 changed files with 120 additions and 10 deletions
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126
src/qemu/qemu_driver.c
View File

@ -104,7 +104,7 @@
#define QEMU_NB_NUMA_PARAM 2
#define QEMU_NB_TOTAL_CPU_STAT_PARAM 3
#define QEMU_NB_PER_CPU_STAT_PARAM 1
#define QEMU_NB_PER_CPU_STAT_PARAM 2
#if HAVE_LINUX_KVM_H
# include <linux/kvm.h>
@ -12563,8 +12563,69 @@ qemuDomainGetTotalcpuStats(virCgroupPtr group,
return nparams;
}
/* This function gets the sums of cpu time consumed by all vcpus.
* For example, if there are 4 physical cpus, and 2 vcpus in a domain,
* then for each vcpu, the cpuacct.usage_percpu looks like this:
* t0 t1 t2 t3
* and we have 2 groups of such data:
* v\p 0 1 2 3
* 0 t00 t01 t02 t03
* 1 t10 t11 t12 t13
* for each pcpu, the sum is cpu time consumed by all vcpus.
* s0 = t00 + t10
* s1 = t01 + t11
* s2 = t02 + t12
* s3 = t03 + t13
*/
static int
getSumVcpuPercpuStats(virCgroupPtr group,
unsigned int nvcpu,
unsigned long long *sum_cpu_time,
unsigned int num)
{
int ret = -1;
int i;
char *buf = NULL;
virCgroupPtr group_vcpu = NULL;
for (i = 0; i < nvcpu; i++) {
char *pos;
unsigned long long tmp;
int j;
if (virCgroupForVcpu(group, i, &group_vcpu, 0) < 0) {
qemuReportError(VIR_ERR_INTERNAL_ERROR,
_("error accessing cgroup cpuacct for vcpu"));
goto cleanup;
}
if (virCgroupGetCpuacctPercpuUsage(group, &buf) < 0)
goto cleanup;
pos = buf;
for (j = 0; j < num; j++) {
if (virStrToLong_ull(pos, &pos, 10, &tmp) < 0) {
qemuReportError(VIR_ERR_INTERNAL_ERROR,
_("cpuacct parse error"));
goto cleanup;
}
sum_cpu_time[j] += tmp;
}
virCgroupFree(&group_vcpu);
VIR_FREE(buf);
}
ret = 0;
cleanup:
virCgroupFree(&group_vcpu);
VIR_FREE(buf);
return ret;
}
static int
qemuDomainGetPercpuStats(virDomainPtr domain,
virDomainObjPtr vm,
virCgroupPtr group,
virTypedParameterPtr params,
unsigned int nparams,
@ -12572,20 +12633,24 @@ qemuDomainGetPercpuStats(virDomainPtr domain,
unsigned int ncpus)
{
char *map = NULL;
char *map2 = NULL;
int rv = -1;
int i, max_id;
char *pos;
char *buf = NULL;
unsigned long long *sum_cpu_time = NULL;
unsigned long long *sum_cpu_pos;
unsigned int n = 0;
qemuDomainObjPrivatePtr priv = vm->privateData;
virTypedParameterPtr ent;
int param_idx;
unsigned long long cpu_time;
/* return the number of supported params */
if (nparams == 0 && ncpus != 0)
return QEMU_NB_PER_CPU_STAT_PARAM; /* only cpu_time is supported */
return QEMU_NB_PER_CPU_STAT_PARAM;
/* return percpu cputime in index 0 */
param_idx = 0;
/* to parse account file, we need "present" cpu map */
/* To parse account file, we need "present" cpu map. */
map = nodeGetCPUmap(domain->conn, &max_id, "present");
if (!map)
return rv;
@ -12608,30 +12673,73 @@ qemuDomainGetPercpuStats(virDomainPtr domain,
pos = buf;
memset(params, 0, nparams * ncpus);
/* return percpu cputime in index 0 */
param_idx = 0;
if (max_id - start_cpu > ncpus - 1)
max_id = start_cpu + ncpus - 1;
for (i = 0; i <= max_id; i++) {
unsigned long long cpu_time;
if (!map[i]) {
cpu_time = 0;
} else if (virStrToLong_ull(pos, &pos, 10, &cpu_time) < 0) {
qemuReportError(VIR_ERR_INTERNAL_ERROR,
_("cpuacct parse error"));
goto cleanup;
} else {
n++;
}
if (i < start_cpu)
continue;
ent = &params[ (i - start_cpu) * nparams + param_idx];
ent = &params[(i - start_cpu) * nparams + param_idx];
if (virTypedParameterAssign(ent, VIR_DOMAIN_CPU_STATS_CPUTIME,
VIR_TYPED_PARAM_ULLONG, cpu_time) < 0)
goto cleanup;
}
/* return percpu vcputime in index 1 */
if (++param_idx >= nparams) {
rv = nparams;
goto cleanup;
}
if (VIR_ALLOC_N(sum_cpu_time, n) < 0) {
virReportOOMError();
goto cleanup;
}
if (getSumVcpuPercpuStats(group, priv->nvcpupids, sum_cpu_time, n) < 0)
goto cleanup;
/* Check that the mapping of online cpus didn't change mid-parse. */
map2 = nodeGetCPUmap(domain->conn, &max_id, "present");
if (!map2 || memcmp(map, map2, VIR_DOMAIN_CPUMASK_LEN) != 0) {
qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("the set of online cpus changed while reading"));
goto cleanup;
}
sum_cpu_pos = sum_cpu_time;
for (i = 0; i <= max_id; i++) {
if (!map[i])
cpu_time = 0;
else
cpu_time = *(sum_cpu_pos++);
if (i < start_cpu)
continue;
if (virTypedParameterAssign(&params[(i - start_cpu) * nparams +
param_idx],
VIR_DOMAIN_CPU_STATS_VCPUTIME,
VIR_TYPED_PARAM_ULLONG,
cpu_time) < 0)
goto cleanup;
}
rv = param_idx + 1;
cleanup:
VIR_FREE(sum_cpu_time);
VIR_FREE(buf);
VIR_FREE(map);
VIR_FREE(map2);
return rv;
}
@ -12683,7 +12791,7 @@ qemuDomainGetCPUStats(virDomainPtr domain,
if (start_cpu == -1)
ret = qemuDomainGetTotalcpuStats(group, params, nparams);
else
ret = qemuDomainGetPercpuStats(domain, group, params, nparams,
ret = qemuDomainGetPercpuStats(domain, vm, group, params, nparams,
start_cpu, ncpus);
cleanup:
virCgroupFree(&group);

4
src/util/cgroup.c
View File

@ -530,7 +530,9 @@ static int virCgroupMakeGroup(virCgroupPtr parent, virCgroupPtr group,
continue;
/* We need to control cpu bandwidth for each vcpu now */
if ((flags & VIR_CGROUP_VCPU) && (i != VIR_CGROUP_CONTROLLER_CPU)) {
if ((flags & VIR_CGROUP_VCPU) &&
(i != VIR_CGROUP_CONTROLLER_CPU &&
i != VIR_CGROUP_CONTROLLER_CPUACCT)) {
/* treat it as unmounted and we can use virCgroupAddTask */
VIR_FREE(group->controllers[i].mountPoint);
continue;