[libvirt] [PATCH 3/9] perf: add page_faults software perf event support

John Ferlan jferlan at redhat.com
Thu Feb 9 21:45:48 UTC 2017



On 01/27/2017 06:01 AM, Nitesh Konkar wrote:
> This patch adds support and documentation
> for the page_faults perf event.
> 
> Signed-off-by: Nitesh Konkar <nitkon12 at linux.vnet.ibm.com>
> ---
>  docs/formatdomain.html.in                   |  6 ++++++
>  docs/news.xml                               |  4 ++--
>  docs/schemas/domaincommon.rng               |  1 +
>  include/libvirt/libvirt-domain.h            | 11 +++++++++++
>  src/libvirt-domain.c                        |  2 ++
>  src/qemu/qemu_driver.c                      |  1 +
>  src/util/virperf.c                          |  7 +++++--
>  src/util/virperf.h                          |  1 +
>  tests/genericxml2xmlindata/generic-perf.xml |  1 +
>  tools/virsh.pod                             |  3 +++
>  10 files changed, 33 insertions(+), 4 deletions(-)
> 
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index 1ed5db7..2071eea 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -1939,6 +1939,7 @@
>    <event name='ref_cpu_cycles' enabled='no'/>
>    <event name='cpu_clock' enabled='no'/>
>    <event name='task_clock' enabled='no'/>
> +  <event name='page_faults' enabled='no'/>
>  </perf>
>  ...
>  </pre>
> @@ -2027,6 +2028,11 @@
>        <td>the count of task clock by applications running on the platform</td>
>        <td><code>perf.task_clock</code></td>
>      </tr>
> +    <tr>
> +      <td><code>page_faults</code></td>
> +      <td>the count of page faults by applications running on the platform</td>
> +      <td><code>perf.page_faults</code></td>
> +    </tr>

Curious why "page_faults" and "page_faults_min" & "page_faults_maj" is
"min+maj" equal to this value?

A nit, I've seen wording like "page faults incurred" used too..  Just a
bit more descriptive

>    </table>
>  
>      <h3><a name="elementsDevices">Devices</a></h3>
> diff --git a/docs/news.xml b/docs/news.xml
> index 38373c0..14beed6 100644
> --- a/docs/news.xml
> +++ b/docs/news.xml
> @@ -137,8 +137,8 @@
>            Add support to get the count of branch instructions
>            executed, branch misses, bus cycles, stalled frontend
>            cpu cycles, stalled backend cpu cycles, ref cpu cycles,
> -          cpu clock and task clock by applications running on the
> -          platform.
> +          cpu clock, task clock and page faults by applications
> +          running on the platform.

Similar with the news.xml to previous...

>          </description>
>        </change>
>        <change>
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index 6ee2c6f..a7727e7 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -435,6 +435,7 @@
>                <value>ref_cpu_cycles</value>
>                <value>cpu_clock</value>
>                <value>task_clock</value>
> +              <value>page_faults</value>
>              </choice>
>            </attribute>
>            <attribute name="enabled">
> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> index f4f1c74..36619b5 100644
> --- a/include/libvirt/libvirt-domain.h
> +++ b/include/libvirt/libvirt-domain.h
> @@ -2208,6 +2208,17 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats);
>   */
>  # define VIR_PERF_PARAM_TASK_CLOCK "task_clock"
>  
> +/**
> +* VIR_PERF_PARAM_PAGE_FAULTS:
> +*
> +* Macro for typed parameter name that represents page_faults
> +* perf event which can be used to measure the count of page
> +* faults by applications running on the platform. It corresponds
> +* to the "perf.page_faults" field in the *Stats APIs.
> +*/
> +# define VIR_PERF_PARAM_PAGE_FAULTS "page_faults"
> +
> +
>  int virDomainGetPerfEvents(virDomainPtr dom,
>                             virTypedParameterPtr *params,
>                             int *nparams,
> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> index 6875848..a923acc 100644
> --- a/src/libvirt-domain.c
> +++ b/src/libvirt-domain.c
> @@ -11254,6 +11254,8 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
>   *                        produced by the cpu_clock perf event.
>   *     "perf.task_clock" - The count of task clock as unsigned long long. It is
>   *                         produced by the task_clock perf event.
> + *     "perf.page_faults" - The count of page faults as unsigned long long. It is
> + *                         produced by the page_faults perf event.
>   *
>   * Note that entire stats groups or individual stat fields may be missing from
>   * the output in case they are not supported by the given hypervisor, are not
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 285156d..88f649e 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -9551,6 +9551,7 @@ qemuDomainSetPerfEvents(virDomainPtr dom,
>                                 VIR_PERF_PARAM_REF_CPU_CYCLES, VIR_TYPED_PARAM_BOOLEAN,
>                                 VIR_PERF_PARAM_CPU_CLOCK, VIR_TYPED_PARAM_BOOLEAN,
>                                 VIR_PERF_PARAM_TASK_CLOCK, VIR_TYPED_PARAM_BOOLEAN,
> +                               VIR_PERF_PARAM_PAGE_FAULTS, VIR_TYPED_PARAM_BOOLEAN,
>                                 NULL) < 0)
>          return -1;
>  
> diff --git a/src/util/virperf.c b/src/util/virperf.c
> index e19cfea..3282aca 100644
> --- a/src/util/virperf.c
> +++ b/src/util/virperf.c
> @@ -44,7 +44,7 @@ VIR_ENUM_IMPL(virPerfEvent, VIR_PERF_EVENT_LAST,
>                "branch_instructions", "branch_misses",
>                "bus_cycles", "stalled_cycles_frontend",
>                "stalled_cycles_backend", "ref_cpu_cycles",
> -              "cpu_clock", "task_clock");
> +              "cpu_clock", "task_clock", "page_faults");
>  
>  struct virPerfEvent {
>      int type;
> @@ -118,7 +118,10 @@ static struct virPerfEventAttr attrs[] = {
>       .attrConfig = PERF_COUNT_SW_CPU_CLOCK},
>      {.type = VIR_PERF_EVENT_TASK_CLOCK,
>       .attrType = PERF_TYPE_SOFTWARE,
> -     .attrConfig = PERF_COUNT_SW_TASK_CLOCK}
> +     .attrConfig = PERF_COUNT_SW_TASK_CLOCK},
> +    {.type = VIR_PERF_EVENT_PAGE_FAULTS,
> +     .attrType = PERF_TYPE_SOFTWARE,
> +     .attrConfig = PERF_COUNT_SW_PAGE_FAULTS},
>  };
>  typedef struct virPerfEventAttr *virPerfEventAttrPtr;
>  
> diff --git a/src/util/virperf.h b/src/util/virperf.h
> index b9e8a75..fbc5ae3 100644
> --- a/src/util/virperf.h
> +++ b/src/util/virperf.h
> @@ -49,6 +49,7 @@ typedef enum {
>      VIR_PERF_EVENT_REF_CPU_CYCLES,   /* Count of ref cpu cycles */
>      VIR_PERF_EVENT_CPU_CLOCK,   /* Count of cpu clock */
>      VIR_PERF_EVENT_TASK_CLOCK,   /* Count of task clock */
> +    VIR_PERF_EVENT_PAGE_FAULTS,   /* Count of page faults */
>  
>      VIR_PERF_EVENT_LAST
>  } virPerfEventType;
> diff --git a/tests/genericxml2xmlindata/generic-perf.xml b/tests/genericxml2xmlindata/generic-perf.xml
> index 5ebc0a2..3f27887 100644
> --- a/tests/genericxml2xmlindata/generic-perf.xml
> +++ b/tests/genericxml2xmlindata/generic-perf.xml
> @@ -28,6 +28,7 @@
>      <event name='ref_cpu_cycles' enabled='yes'/>
>      <event name='cpu_clock' enabled='yes'/>
>      <event name='task_clock' enabled='yes'/>
> +    <event name='page_faults' enabled='yes'/>
>    </perf>
>    <devices>
>    </devices>
> diff --git a/tools/virsh.pod b/tools/virsh.pod
> index 958e473..f7be74e 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -948,6 +948,7 @@ I<--perf> returns the statistics of all enabled perf events:
>  "perf.ref_cpu_cycles" - the count of ref cpu cycles
>  "perf.cpu_clock" - the count of cpu clock
>  "perf.task_clock" - the count of task clock
> +"perf.page_faults" - the count of page faults
>  
>  See the B<perf> command for more details about each event.
>  
> @@ -2316,6 +2317,8 @@ B<Valid perf event names>
>                running on the platform.
>    task_clock - Provides the task clock time consumed by applications
>                 running on the platform
> +  page_faults - Provides the count of page faults by applications
> +                running on the platform

Interesting that the maj and min descriptions are quite wordy, but this
one isn't...  I'm assuming to a degree the count the same thing, right?

John
>  
>  B<Note>: The statistics can be retrieved using the B<domstats> command using
>  the I<--perf> flag.
> 




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