[dpdk-dev] [PATCH v5] ether: add support for vtune task tracing

[Jerin Jacob]

-----Original Message-----
> Date: Wed, 19 Jul 2017 11:54:45 +0300
> From: ilia.kurakin at intel.com
> To: dev at dpdk.org
> CC: jerin.jacob at caviumnetworks.com, konstantin.ananyev at intel.com,
>  keith.wiles at intel.com, dmitry.galanov at intel.com, Ilia Kurakin
>  <ilia.kurakin at intel.com>
> Subject: [PATCH v5] ether: add support for vtune task tracing
> X-Mailer: git-send-email 2.7.4
> 
> From: Ilia Kurakin <ilia.kurakin at intel.com>
> 
> The patch adds tracing of loop iterations that yielded no packets in a DPDK
> application. It is using ITT task API:
>     https://software.intel.com/en-us/node/544206
> 
> We suppose the flow of using this tracing would assume the user has ITT lib
> and header on machine and re-build DPDK with additional make parameters:
> 
>     make EXTRA_CFLAGS=-I<path to ittnotify.h>
>          EXTRA_LDLIBS="-L<path to libittnotify.a> -littnotify"
> 
> Signed-off-by: Ilia Kurakin <ilia.kurakin at intel.com>

Found a checkpatch issue.

➜ [master][dpdk.org] $ ./devtools/checkpatches.sh 

### ether: add support for vtune task tracing

ERROR:SPACING: need consistent spacing around '*' (ctx:WxV)
#173: FILE: lib/librte_ether/rte_ethdev_profile.c:59:
+	__itt_domain *domains[RTE_MAX_QUEUES_PER_PORT];
 	             ^

ERROR:SPACING: need consistent spacing around '*' (ctx:WxV)
#177: FILE: lib/librte_ether/rte_ethdev_profile.c:63:
+	__itt_string_handle *handles[RTE_MAX_QUEUES_PER_PORT];
 	                    ^

total: 2 errors, 0 warnings, 278 lines checked

0/1 valid patch


> 
> ---
> 
> -V2 change:
>     ITT tasks collection is moved to rx callback
> 
> -V3 change:
>     rte_ethdev_profile.c created, all profile specific code moved there.
> 
>     Added generic profile function
> 
> -V4 change:
>     checkpatch issues fixed
> 
>     Added documentation topic
> 
> -V5 change:
>     Documentation fixes
> 
> 
>  config/common_base                    |   1 +
>  doc/guides/prog_guide/profile_app.rst |  34 ++++++++
>  lib/librte_ether/Makefile             |   1 +
>  lib/librte_ether/rte_ethdev.c         |   4 +
>  lib/librte_ether/rte_ethdev_profile.c | 156 ++++++++++++++++++++++++++++++++++
>  lib/librte_ether/rte_ethdev_profile.h |  52 ++++++++++++
>  6 files changed, 248 insertions(+)
>  create mode 100644 lib/librte_ether/rte_ethdev_profile.c
>  create mode 100644 lib/librte_ether/rte_ethdev_profile.h
> 
> diff --git a/config/common_base b/config/common_base
> index 8ae6e92..dda51db 100644
> --- a/config/common_base
> +++ b/config/common_base
> @@ -136,6 +136,7 @@ CONFIG_RTE_MAX_QUEUES_PER_PORT=1024
>  CONFIG_RTE_LIBRTE_IEEE1588=n
>  CONFIG_RTE_ETHDEV_QUEUE_STAT_CNTRS=16
>  CONFIG_RTE_ETHDEV_RXTX_CALLBACKS=y
> +CONFIG_RTE_ETHDEV_PROFILE_ITT_WASTED_RX_ITERATIONS=n
>  
>  #
>  # Turn off Tx preparation stage
> diff --git a/doc/guides/prog_guide/profile_app.rst b/doc/guides/prog_guide/profile_app.rst
> index 54b546a..590cb72 100644
> --- a/doc/guides/prog_guide/profile_app.rst
> +++ b/doc/guides/prog_guide/profile_app.rst
> @@ -59,6 +59,40 @@ Refer to the
>  for details about application profiling.
>  
>  
> +Profiling wasted iterations with ITT
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Iterations that yielded no RX packets (wasted loop iterations) can be analyzed
> +using Intel® VTune\ :sup:`TM` Amplifier. This profiling employs the
> +`Instrumentation and Tracing Technology (ITT) API
> +<https://software.intel.com/en-us/node/544195>`_
> +feature of VTune Amplifier and requires only reconfiguring of DPDK library,
> +no changes in a DPDK application are needed.
> +
> +To trace wasted iterations on RX queues, first reconfigure DPDK with
> +``CONFIG_RTE_ETHDEV_RXTX_CALLBACKS`` and
> +``CONFIG_RTE_ETHDEV_PROFILE_ITT_WASTED_RX_ITERATIONS`` enabled.
> +
> +Then rebuild DPDK, specifying paths to the ITT header and library, which can
> +be found in any VTune Amplifier distribution in the *include* and *lib*
> +directories respectively:
> +
> +.. code-block:: console
> +
> +    make EXTRA_CFLAGS=-I<path to ittnotify.h> \
> +         EXTRA_LDLIBS="-L<path to libittnotify.a> -littnotify"
> +
> +Finally, to see wasted iterations in your performance analysis results,
> +select the *"Analyze user tasks, events, and counters"* checkbox in the
> +*"Analysis Type"* tab when configuring analysis via VTune Amplifier GUI.
> +Alternatively, when running VTune Amplifier via command line, specify
> +``-knob enable-user-tasks=true`` option.
> +
> +Collected regions of wasted iterations will be marked on VTune Amplifier's
> +timeline as ITT tasks. These ITT tasks have predefined names, containing
> +Ethernet device and RX queue identifiers.

Documentation changes could move to different patch for better review.

> diff --git a/lib/librte_ether/rte_ethdev_profile.h b/lib/librte_ether/rte_ethdev_profile.h
> new file mode 100644
> index 0000000..1eb72bd
> +/**
> + * Initialization of profiling RX queues for the Ethernet device.
> + * Implementation of this function depends on chosen profiling method,
> + * defined in configs.
> + *
> + * @param port_id
> + *  The port identifier of the Ethernet device.
> + * @param dev
> + *  Pointer to struct rte_eth_dev corresponding to given port_id.
> + */
> +void
> +rte_eth_profile_rx_init(uint8_t port_id, struct rte_eth_dev *dev);

better to prefix __ for internal function(i.e __rte_eth_profile_rx_init)

With above suggested changes:

Acked-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>


> +
> +#endif
> -- 
> 2.7.4
> 
> 
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