[libvirt] [PATCH 4/9] perf: add context_switches software perf event support
John Ferlan
jferlan at redhat.com
Thu Feb 9 21:47:57 UTC 2017
On 01/27/2017 06:01 AM, Nitesh Konkar wrote:
> This patch adds support and documentation
> for the context_switches 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 | 10 ++++++++++
> src/libvirt-domain.c | 3 +++
> src/qemu/qemu_driver.c | 1 +
> src/util/virperf.c | 6 +++++-
> src/util/virperf.h | 1 +
> tests/genericxml2xmlindata/generic-perf.xml | 1 +
> tools/virsh.pod | 3 +++
> 10 files changed, 33 insertions(+), 3 deletions(-)
>
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index 2071eea..4ed6e02 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -1940,6 +1940,7 @@
> <event name='cpu_clock' enabled='no'/>
> <event name='task_clock' enabled='no'/>
> <event name='page_faults' enabled='no'/>
> + <event name='context_switches' enabled='no'/>
> </perf>
> ...
> </pre>
> @@ -2033,6 +2034,11 @@
> <td>the count of page faults by applications running on the platform</td>
> <td><code>perf.page_faults</code></td>
> </tr>
> + <tr>
> + <td><code>context_switches</code></td>
> + <td>the count of context switches by applications running on the platform</td>
> + <td><code>perf.context_switches</code></td>
> + </tr>
> </table>
>
> <h3><a name="elementsDevices">Devices</a></h3>
> diff --git a/docs/news.xml b/docs/news.xml
> index 14beed6..fb872f5 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, task clock and page faults by applications
> - running on the platform.
> + cpu clock, task clock, page faults and context switches
> + by applications running on the platform.
Remove news.xml from this patch... like previous...
> </description>
> </change>
> <change>
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index a7727e7..e4e1358 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -436,6 +436,7 @@
> <value>cpu_clock</value>
> <value>task_clock</value>
> <value>page_faults</value>
> + <value>context_switches</value>
> </choice>
> </attribute>
> <attribute name="enabled">
> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> index 36619b5..e71bfa7 100644
> --- a/include/libvirt/libvirt-domain.h
> +++ b/include/libvirt/libvirt-domain.h
> @@ -2218,6 +2218,16 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats);
> */
> # define VIR_PERF_PARAM_PAGE_FAULTS "page_faults"
>
> +/**
> + * VIR_PERF_PARAM_CONTEXT_SWITCHES:
> + *
> + * Macro for typed parameter name that represents context_switches
> + * perf event which can be used to measure the count of context
> + * switches by applications running on the platform. It corresponds
> + * to the "perf.context_switches" field in the *Stats APIs.
> + */
> +# define VIR_PERF_PARAM_CONTEXT_SWITCHES "context_switches"
> +
>
> int virDomainGetPerfEvents(virDomainPtr dom,
> virTypedParameterPtr *params,
> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> index a923acc..42720f1 100644
> --- a/src/libvirt-domain.c
> +++ b/src/libvirt-domain.c
> @@ -11256,6 +11256,9 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
> * 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.
> + * "perf.context_switches" - The count of context switches as unsigned long
> + * long. It is produced by the context_switches
> + * 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 88f649e..c579b61 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -9552,6 +9552,7 @@ qemuDomainSetPerfEvents(virDomainPtr dom,
> 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,
> + VIR_PERF_PARAM_CONTEXT_SWITCHES, VIR_TYPED_PARAM_BOOLEAN,
> NULL) < 0)
> return -1;
>
> diff --git a/src/util/virperf.c b/src/util/virperf.c
> index 3282aca..c004061 100644
> --- a/src/util/virperf.c
> +++ b/src/util/virperf.c
> @@ -44,7 +44,8 @@ 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", "page_faults");
> + "cpu_clock", "task_clock", "page_faults",
> + "context_switches");
>
> struct virPerfEvent {
> int type;
> @@ -122,6 +123,9 @@ static struct virPerfEventAttr attrs[] = {
> {.type = VIR_PERF_EVENT_PAGE_FAULTS,
> .attrType = PERF_TYPE_SOFTWARE,
> .attrConfig = PERF_COUNT_SW_PAGE_FAULTS},
> + {.type = VIR_PERF_EVENT_CONTEXT_SWITCHES,
> + .attrType = PERF_TYPE_SOFTWARE,
> + .attrConfig = PERF_COUNT_SW_CONTEXT_SWITCHES},
> };
> typedef struct virPerfEventAttr *virPerfEventAttrPtr;
>
> diff --git a/src/util/virperf.h b/src/util/virperf.h
> index fbc5ae3..b937d9a 100644
> --- a/src/util/virperf.h
> +++ b/src/util/virperf.h
> @@ -50,6 +50,7 @@ typedef enum {
> 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_CONTEXT_SWITCHES, /* Count of context switches */
>
> VIR_PERF_EVENT_LAST
> } virPerfEventType;
> diff --git a/tests/genericxml2xmlindata/generic-perf.xml b/tests/genericxml2xmlindata/generic-perf.xml
> index 3f27887..29a2273 100644
> --- a/tests/genericxml2xmlindata/generic-perf.xml
> +++ b/tests/genericxml2xmlindata/generic-perf.xml
> @@ -29,6 +29,7 @@
> <event name='cpu_clock' enabled='yes'/>
> <event name='task_clock' enabled='yes'/>
> <event name='page_faults' enabled='yes'/>
> + <event name='context_switches' enabled='yes'/>
> </perf>
> <devices>
> </devices>
> diff --git a/tools/virsh.pod b/tools/virsh.pod
> index f7be74e..d0bf016 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -949,6 +949,7 @@ I<--perf> returns the statistics of all enabled perf events:
> "perf.cpu_clock" - the count of cpu clock
> "perf.task_clock" - the count of task clock
> "perf.page_faults" - the count of page faults
> +"perf.context_switches" - the count of context switches
>
> See the B<perf> command for more details about each event.
>
> @@ -2319,6 +2320,8 @@ B<Valid perf event names>
> running on the platform
> page_faults - Provides the count of page faults by applications
> running on the platform
> + context_switches - Provides the count of context switches by applications
> + running on the platform
This description needs to have it's formatting fixed a bit - to not go
past the 80 column windows.. After building use man tools/virsh.1 with
an 80 column wide terminal.
John
>
> B<Note>: The statistics can be retrieved using the B<domstats> command using
> the I<--perf> flag.
>
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