[libvirt] [PATCH] perf: add branch_misses perf event support

John Ferlan jferlan at redhat.com
Mon Dec 12 23:13:25 UTC 2016



On 12/11/2016 08:30 AM, Nitesh Konkar wrote:
> This patch adds support and documentation
> for the branch_misses perf event.
> 
> Signed-off-by: Nitesh Konkar <nitkon12 at linux.vnet.ibm.com>
> ---
>  docs/formatdomain.html.in                   |  6 ++++++
>  docs/schemas/domaincommon.rng               |  1 +
>  include/libvirt/libvirt-domain.h            | 10 ++++++++++
>  src/libvirt-domain.c                        |  4 ++++
>  src/qemu/qemu_driver.c                      |  1 +
>  src/util/virperf.c                          |  5 ++++-
>  src/util/virperf.h                          |  1 +
>  tests/genericxml2xmlindata/generic-perf.xml |  1 +
>  tools/virsh.pod                             |  5 ++++-
>  9 files changed, 32 insertions(+), 2 deletions(-)
> 

In the future - adjusting docs/news.html.in should also be done. I've
done that for you so that the next one added has the example (more or
less).  It'll be a version specific adjustment.

Anyway - a minor nit below which I changed...

ACK and pushed

John

> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index 9218eec..086af55 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -1928,6 +1928,7 @@
>    <event name='cache_references' enabled='no'/>
>    <event name='cache_misses' enabled='no'/>
>    <event name='branch_instructions' enabled='no'/>
> +  <event name='branch_misses' enabled='no'/>
>  </perf>
>  ...
>  </pre>
> @@ -1978,6 +1979,11 @@
>        <td>the count of branch instructions by applications running on the platform</td>
>        <td><code>perf.branch_instructions</code></td>
>      </tr>
> +    <tr>
> +      <td><code>branch_misses</code></td>
> +      <td>the count of branch misses by applications running on the platform</td>
> +      <td><code>perf.branch_misses</code></td>
> +    </tr>
>    </table>
>  
>      <h3><a name="elementsDevices">Devices</a></h3>
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index c004233..bf8818d 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -428,6 +428,7 @@
>                <value>cache_references</value>
>                <value>cache_misses</value>
>                <value>branch_instructions</value>
> +              <value>branch_misses</value>
>              </choice>
>            </attribute>
>            <attribute name="enabled">
> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> index f43c976..3290b10 100644
> --- a/include/libvirt/libvirt-domain.h
> +++ b/include/libvirt/libvirt-domain.h
> @@ -2135,6 +2135,16 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats);
>   */
>  # define VIR_PERF_PARAM_BRANCH_INSTRUCTIONS "branch_instructions"
>  
> +/**
> + * VIR_PERF_PARAM_BRANCH_MISSES:
> + *
> + * Macro for typed parameter name that represents branch_misses
> + * perf event which can be used to measure the count of branch misses
> + * by applications running on the platform. It corresponds to the
> + * "perf.branch_misses" field in the *Stats APIs.
> + */
> +# define VIR_PERF_PARAM_BRANCH_MISSES "branch_misses"
> +
>  int virDomainGetPerfEvents(virDomainPtr dom,
>                             virTypedParameterPtr *params,
>                             int *nparams,
> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> index 6481abf..a91f432 100644
> --- a/src/libvirt-domain.c
> +++ b/src/libvirt-domain.c
> @@ -11229,6 +11229,10 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
>   *     "perf.branch_instructions" - The count of branch instructions as
>   *                                  unsigned long long. It is produced by
>   *                                  branch_instructions perf event.
> + *     "perf.branch_misses"       - The count of branch misses as
> + *                                  unsigned long long. It is produced by
> + *                                  branch_misses perf event.


FYI: No need to bother with extra indents to attempt to keep things aligned.

> + *
>   *
>   * 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 842de0a..0f3a283 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -9853,6 +9853,7 @@ qemuDomainSetPerfEvents(virDomainPtr dom,
>                                 VIR_PERF_PARAM_CACHE_REFERENCES, VIR_TYPED_PARAM_BOOLEAN,
>                                 VIR_PERF_PARAM_CACHE_MISSES, VIR_TYPED_PARAM_BOOLEAN,
>                                 VIR_PERF_PARAM_BRANCH_INSTRUCTIONS, VIR_TYPED_PARAM_BOOLEAN,
> +                               VIR_PERF_PARAM_BRANCH_MISSES, VIR_TYPED_PARAM_BOOLEAN,
>                                 NULL) < 0)
>          return -1;
>  
> diff --git a/src/util/virperf.c b/src/util/virperf.c
> index 635faf1..7f630da 100644
> --- a/src/util/virperf.c
> +++ b/src/util/virperf.c
> @@ -41,7 +41,7 @@ VIR_ENUM_IMPL(virPerfEvent, VIR_PERF_EVENT_LAST,
>                "cmt", "mbmt", "mbml",
>                "cpu_cycles", "instructions",
>                "cache_references", "cache_misses",
> -              "branch_instructions");
> +              "branch_instructions", "branch_misses");
>  
>  struct virPerfEvent {
>      int type;
> @@ -89,6 +89,9 @@ static struct virPerfEventAttr attrs[] = {
>      {.type = VIR_PERF_EVENT_BRANCH_INSTRUCTIONS,
>       .attrType = PERF_TYPE_HARDWARE,
>       .attrConfig = PERF_COUNT_HW_BRANCH_INSTRUCTIONS},
> +    {.type = VIR_PERF_EVENT_BRANCH_MISSES,
> +     .attrType = PERF_TYPE_HARDWARE,
> +     .attrConfig = PERF_COUNT_HW_BRANCH_MISSES},
>  };
>  typedef struct virPerfEventAttr *virPerfEventAttrPtr;
>  
> diff --git a/src/util/virperf.h b/src/util/virperf.h
> index 8ebc03c..7049a5b 100644
> --- a/src/util/virperf.h
> +++ b/src/util/virperf.h
> @@ -38,6 +38,7 @@ typedef enum {
>      VIR_PERF_EVENT_CACHE_MISSES,     /* Cache misses by applications */
>      VIR_PERF_EVENT_BRANCH_INSTRUCTIONS, /* Count of branch instructions
>                                             for applications */
> +    VIR_PERF_EVENT_BRANCH_MISSES,  /* Count of branch misses for applications */
>  
>      VIR_PERF_EVENT_LAST
>  } virPerfEventType;
> diff --git a/tests/genericxml2xmlindata/generic-perf.xml b/tests/genericxml2xmlindata/generic-perf.xml
> index 92e5847..a1e4e1c 100644
> --- a/tests/genericxml2xmlindata/generic-perf.xml
> +++ b/tests/genericxml2xmlindata/generic-perf.xml
> @@ -21,6 +21,7 @@
>      <event name='cache_references' enabled='no'/>
>      <event name='cache_misses' enabled='no'/>
>      <event name='branch_instructions' enabled='yes'/>
> +    <event name='branch_misses' enabled='yes'/>
>    </perf>
>    <devices>
>    </devices>
> diff --git a/tools/virsh.pod b/tools/virsh.pod
> index 869062a..74c05c9 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -946,7 +946,8 @@ I<--perf> returns the statistics of all enabled perf events:
>  "perf.instructions" - the count of instructions,
>  "perf.cache_references" - the count of cache hits,
>  "perf.cache_misses" - the count of caches misses,
> -"perf.branch_instructions" - the count of application branch instructions
> +"perf.branch_instructions" - the count of branch instructions,
> +"perf.branch_misses" - the count of branch misses
>  
>  See the B<perf> command for more details about each event.
>  
> @@ -2296,6 +2297,8 @@ B<Valid perf event names>
>    branch_instructions - Provides the count of branch instructions
>                          executed by applications running on the
>                          platform.
> +  branch_misses    - Provides the count of branch misses executed
> +                     by applications running on the platform.
>  
>  B<Note>: The statistics can be retrieved using the B<domstats> command using
>  the I<--perf> flag.
> 




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