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Re: [libvirt] [PATCHv10 3/4] qemu: Report cache occupancy (CMT) with domstats




On 11/26/18 12:56 PM, Wang Huaqiang wrote:
> Adding the interface in qemu to report CMT statistic information
> through command 'virsh domstats --cpu-total'.
> 
> Below is a typical output:
> 
>          # virsh domstats 1 --cpu-total
>          Domain: 'ubuntu16.04-base'
>            ...
>            cpu.cache.monitor.count=2
>            cpu.cache.monitor.0.name=vcpus_1
>            cpu.cache.monitor.0.vcpus=1
>            cpu.cache.monitor.0.bank.count=2
>            cpu.cache.monitor.0.bank.0.id=0
>            cpu.cache.monitor.0.bank.0.bytes=4505600
>            cpu.cache.monitor.0.bank.1.id=1
>            cpu.cache.monitor.0.bank.1.bytes=5586944
>            cpu.cache.monitor.1.name=vcpus_4-6
>            cpu.cache.monitor.1.vcpus=4,5,6
>            cpu.cache.monitor.1.bank.count=2
>            cpu.cache.monitor.1.bank.0.id=0
>            cpu.cache.monitor.1.bank.0.bytes=17571840
>            cpu.cache.monitor.1.bank.1.id=1
>            cpu.cache.monitor.1.bank.1.bytes=29106176
> 
> Signed-off-by: Wang Huaqiang <huaqiang wang intel com>
> ---
>  src/libvirt-domain.c   |  12 ++++
>  src/qemu/qemu_driver.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  tools/virsh.pod        |  14 ++++
>  3 files changed, 208 insertions(+), 1 deletion(-)
> 
> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> index 5b76458..73d602e 100644
> --- a/src/libvirt-domain.c
> +++ b/src/libvirt-domain.c
> @@ -11415,6 +11415,18 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
>   *     "cpu.user" - user cpu time spent in nanoseconds as unsigned long long.
>   *     "cpu.system" - system cpu time spent in nanoseconds as unsigned long
>   *                    long.
> + *     "cpu.cache.monitor.count" - the number of cache monitors for this domain
> + *     "cpu.cache.monitor.<num>.name" - the name of cache monitor <num>
> + *     "cpu.cache.monitor.<num>.vcpus" - vcpu list of cache monitor <num>
> + *     "cpu.cache.monitor.<num>.bank.count" - the number of cache banks in
> + *                                            cache monitor <num>
> + *     "cpu.cache.monitor.<num>.bank.<index>.id" - host allocated cache id for
> + *                                                 bank <index> in cache
> + *                                                 monitor <num>
> + *     "cpu.cache.monitor.<num>.bank.<index>.bytes" - the number of bytes of
> + *                                                    last level cache that the
> + *                                                    domain is using on cache
> + *                                                    bank <index>
>   *
>   * VIR_DOMAIN_STATS_BALLOON:
>   *     Return memory balloon device information.
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 7fb9102..ac2be35 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -19929,6 +19929,181 @@ typedef enum {
>  #define HAVE_JOB(flags) ((flags) & QEMU_DOMAIN_STATS_HAVE_JOB)
>  
>  
> +typedef struct _virQEMUResctrlMonData virQEMUResctrlMonData;
> +typedef virQEMUResctrlMonData *virQEMUResctrlMonDataPtr;
> +struct _virQEMUResctrlMonData {
> +    char *name;
> +    char *vcpus;
> +    virResctrlMonitorStatsPtr *stats;
> +    size_t nstats;
> +};
> +
> +
> +static void
> +qemuDomainFreeResctrlMonData(virQEMUResctrlMonDataPtr *resdata,
> +                             size_t nresdata)
> +{
> +    size_t i = 0;
> +
> +    for (i = 0; i < nresdata; i++) {
> +        VIR_FREE(resdata[i]->name);
> +        VIR_FREE(resdata[i]->vcpus);
> +        virResctrlMonitorFreeStats(resdata[i]->stats, resdata[i]->nstats);
> +        VIR_FREE(resdata[i]);
> +    }
> +
> +    VIR_FREE(resdata);
> +}
> +
> +
> +/**
> + * qemuDomainGetResctrlMonData:
> + * @dom: Pointer for the domain that the resctrl monitors reside in
> + * @resdata: Pointer of virQEMUResctrlMonDataPtr pointer for receiving the
> + *            virQEMUResctrlMonDataPtr array. Caller is responsible for
> + *            freeing the array.
> + * @nresdata: Pointer of size_t to report the size virQEMUResctrlMonDataPtr
> + *            array to caller. If * nresdata is not 0, even if function
> + *            returns an error, the caller is also required to call
> + *            qemuDomainFreeResctrlMonData to free the array in * resdata
> + * @tag: Could be VIR_RESCTRL_MONITOR_TYPE_CACHE for getting cache statistics
> + *       from @dom cache monitors. VIR_RESCTRL_MONITOR_TYPE_MEMBW for
> + *       getting memory bandwidth statistics from memory bandwidth monitors.
> + *
> + * Get cache or memory bandwidth statistics from @dom monitors.
> + *
> + * Returns -1 on failure, or 0 on success.
> + */
> +static int
> +qemuDomainGetResctrlMonData(virDomainObjPtr dom,
> +                            virQEMUResctrlMonDataPtr **resdata,
> +                            size_t *nresdata,
> +                            virResctrlMonitorType tag)
> +{
> +    virDomainResctrlDefPtr resctrl = NULL;
> +    virQEMUResctrlMonDataPtr res = NULL;
> +    size_t i = 0;
> +    size_t j = 0;
> +
> +    for (i = 0; i < dom->def->nresctrls; i++) {
> +        resctrl = dom->def->resctrls[i];
> +
> +        for (j = 0; j < resctrl->nmonitors; j++) {
> +            virDomainResctrlMonDefPtr domresmon = NULL;
> +            virResctrlMonitorPtr monitor = NULL;
> +
> +            domresmon = resctrl->monitors[j];
> +            monitor = domresmon->instance;
> +
> +            if (domresmon->tag != tag)
> +                continue;
> +
> +            if (VIR_ALLOC(res) < 0)
> +                return -1;
> +
> +            /* If virBitmapFormat successfully returns an vcpu string, then
> +             * res.vcpus is assigned with an memory space holding it,
> +             * let this newly allocated memory buffer to be freed along with
> +             * the free of 'res' */
> +            if (!(res->vcpus = virBitmapFormat(domresmon->vcpus)))
> +                goto error;
> +
> +            if (VIR_STRDUP(res->name, virResctrlMonitorGetID(monitor)) < 0)
> +                goto error;
> +
> +            if (virResctrlMonitorGetCacheOccupancy(monitor,
> +                                                   &res->stats,
> +                                                   &res->nstats) < 0)
> +                goto error;
> +
> +            if (VIR_APPEND_ELEMENT(*resdata, *nresdata, res) < 0)
> +                goto error;
> +        }
> +    }
> +
> +    return 0;
> +
> + error:
> +    if (res)

Cannot get here with res == NULL

> +        qemuDomainFreeResctrlMonData(&res, 1);

@res is a single element not the array of elements.

What's going on here is closer to what virMediatedDeviceTypeFree does

I'll alter to just take an @resdata and have this called as:

    qemuDomainFreeResctrlMonData(res);

and alter qemuDomainFreeResctrlMonData to just do what's inside the for
loop above.

then...

> +
> +    return -1;
> +}
> +
> +
> +static int
> +qemuDomainGetStatsCpuCache(virDomainObjPtr dom,
> +                           virDomainStatsRecordPtr record,
> +                           int *maxparams)
> +{
> +    char param_name[VIR_TYPED_PARAM_FIELD_LENGTH];
> +    virQEMUResctrlMonDataPtr *resdata = NULL;
> +    size_t nresdata = 0;
> +    size_t i = 0;
> +    size_t j = 0;
> +    int ret = -1;
> +
> +    if (!virDomainObjIsActive(dom))
> +        return 0;
> +
> +    if (qemuDomainGetResctrlMonData(dom, &resdata, &nresdata,
> +                                    VIR_RESCTRL_MONITOR_TYPE_CACHE) < 0)
> +        goto cleanup;
> +
> +    snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH,
> +             "cpu.cache.monitor.count");
> +    if (virTypedParamsAddUInt(&record->params, &record->nparams,
> +                              maxparams, param_name, nresdata) < 0)
> +        goto cleanup;
> +
> +    for (i = 0; i < nresdata; i++) {
> +        snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH,
> +                 "cpu.cache.monitor.%zu.name", i);
> +        if (virTypedParamsAddString(&record->params,
> +                                    &record->nparams,
> +                                    maxparams,
> +                                    param_name,
> +                                    resdata[i]->name) < 0)
> +            goto cleanup;
> +
> +        snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH,
> +                 "cpu.cache.monitor.%zu.vcpus", i);
> +        if (virTypedParamsAddString(&record->params, &record->nparams,
> +                                    maxparams, param_name,
> +                                    resdata[i]->vcpus) < 0)
> +            goto cleanup;
> +
> +        snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH,
> +                 "cpu.cache.monitor.%zu.bank.count", i);
> +        if (virTypedParamsAddUInt(&record->params, &record->nparams,
> +                                  maxparams, param_name,
> +                                  resdata[i]->nstats) < 0)
> +            goto cleanup;
> +
> +        for (j = 0; j < resdata[i]->nstats; j++) {
> +            snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH,
> +                     "cpu.cache.monitor.%zu.bank.%zu.id", i, j);
> +            if (virTypedParamsAddUInt(&record->params, &record->nparams,
> +                                      maxparams, param_name,
> +                                      resdata[i]->stats[j]->id) < 0)
> +                goto cleanup;
> +
> +            snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH,
> +                     "cpu.cache.monitor.%zu.bank.%zu.bytes", i, j);
> +            if (virTypedParamsAddUInt(&record->params, &record->nparams,
> +                                      maxparams, param_name,
> +                                      resdata[i]->stats[j]->val) < 0)
> +                goto cleanup;
> +        }
> +    }
> +
> +    ret = 0;
> + cleanup:
> +    qemuDomainFreeResctrlMonData(resdata, nresdata);

Change this to:

    for (i = 0; i < nresdata; i++)
        qemuDomainFreeResctrlMonData(resdata[i]);
    VIR_FREE(resdata);


Everything else seems fine

John

Most likely bad instructions on my part.

> +    return ret;
> +}
> +
> +
>  static int
>  qemuDomainGetStatsCpuCgroup(virDomainObjPtr dom,
>                              virDomainStatsRecordPtr record,
> @@ -19976,7 +20151,13 @@ qemuDomainGetStatsCpu(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
>                        int *maxparams,
>                        unsigned int privflags ATTRIBUTE_UNUSED)
>  {
> -    return qemuDomainGetStatsCpuCgroup(dom, record, maxparams);
> +    if (qemuDomainGetStatsCpuCgroup(dom, record, maxparams) < 0)
> +        return -1;
> +
> +    if (qemuDomainGetStatsCpuCache(dom, record, maxparams) < 0)
> +        return -1;
> +
> +    return 0;
>  }
>  
>  
> diff --git a/tools/virsh.pod b/tools/virsh.pod
> index 4876656..86a4996 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -1012,6 +1012,20 @@ I<--cpu-total> returns:
>   "cpu.time" - total cpu time spent for this domain in nanoseconds
>   "cpu.user" - user cpu time spent in nanoseconds
>   "cpu.system" - system cpu time spent in nanoseconds
> + "cpu.cache.monitor.count" - the number of cache monitors for this
> +                             domain
> + "cpu.cache.monitor.<num>.name" - the name of cache monitor <num>
> + "cpu.cache.monitor.<num>.vcpus" - vcpu list of cache monitor <num>
> + "cpu.cache.monitor.<num>.bank.count" - the number of cache banks
> +                                        in cache monitor <num>
> + "cpu.cache.monitor.<num>.bank.<index>.id" - host allocated cache id
> +                                             for bank <index> in
> +                                             cache monitor <num>
> + "cpu.cache.monitor.<num>.bank.<index>.bytes" - the number of bytes
> +                                                of last level cache
> +                                                that the domain is
> +                                                using on cache bank
> +                                                <index>
>  
>  I<--balloon> returns:
>  
> 


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