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

ilia.kurakin at intel.com ilia.kurakin at intel.com
Wed Jul 19 10:54:45 CEST 2017


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>

---

-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.
+
+
 Profiling on ARM64
 ------------------
 
diff --git a/lib/librte_ether/Makefile b/lib/librte_ether/Makefile
index db692ae..7224a11 100644
--- a/lib/librte_ether/Makefile
+++ b/lib/librte_ether/Makefile
@@ -46,6 +46,7 @@ LIBABIVER := 6
 SRCS-y += rte_ethdev.c
 SRCS-y += rte_flow.c
 SRCS-y += rte_tm.c
+SRCS-y += rte_ethdev_profile.c
 
 #
 # Export include files
diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index a1b7447..2eba36e 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -67,6 +67,7 @@
 
 #include "rte_ether.h"
 #include "rte_ethdev.h"
+#include "rte_ethdev_profile.h"
 
 static const char *MZ_RTE_ETH_DEV_DATA = "rte_eth_dev_data";
 struct rte_eth_dev rte_eth_devices[RTE_MAX_ETHPORTS];
@@ -825,6 +826,9 @@ rte_eth_dev_configure(uint8_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
 		return diag;
 	}
 
+	/* See rte_ethdev_profile.h to find comments on code below. */
+	rte_eth_profile_rx_init(port_id, dev);
+
 	return 0;
 }
 
diff --git a/lib/librte_ether/rte_ethdev_profile.c b/lib/librte_ether/rte_ethdev_profile.c
new file mode 100644
index 0000000..bb83c8a
--- /dev/null
+++ b/lib/librte_ether/rte_ethdev_profile.c
@@ -0,0 +1,156 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <rte_config.h>
+
+#include "rte_ethdev_profile.h"
+
+/**
+ * This conditional block enables RX queues profiling by tracking wasted
+ * iterations, i.e. iterations which yielded no RX packets. Profiling is
+ * performed using the Instrumentation and Tracing Technology (ITT) API,
+ * employed by the Intel (R) VTune (TM) Amplifier.
+ */
+#ifdef RTE_ETHDEV_PROFILE_ITT_WASTED_RX_ITERATIONS
+
+#include <ittnotify.h>
+
+#define ITT_MAX_NAME_LEN (100)
+
+/**
+ * Auxiliary ITT structure belonging to Ethernet devive and using to:
+ *   -  track RX queue state to determine whether it is wasting loop iterations
+ *   -  begin or end ITT task using task domain and task name (handle)
+ */
+struct itt_profile_rx_data {
+	/**
+	 * ITT domains for each queue.
+	 */
+	__itt_domain *domains[RTE_MAX_QUEUES_PER_PORT];
+	/**
+	 * ITT task names for each queue.
+	 */
+	__itt_string_handle *handles[RTE_MAX_QUEUES_PER_PORT];
+	/**
+	 * Flags indicating the queues state. Possible values:
+	 *   1 - queue is wasting iterations,
+	 *   0 - otherwise.
+	 */
+	uint8_t queue_state[RTE_MAX_QUEUES_PER_PORT];
+};
+
+/**
+ * The pool of *itt_profile_rx_data* structures.
+ */
+struct itt_profile_rx_data itt_rx_data[RTE_MAX_ETHPORTS];
+
+
+/**
+ * This callback function manages ITT tasks collection on given port and queue.
+ * It must be registered with rte_eth_add_rx_callback() to be called from
+ * rte_eth_rx_burst(). To find more comments see rte_rx_callback_fn function
+ * type declaration.
+ */
+static uint16_t
+collect_itt_rx_burst_cb(uint8_t port_id, uint16_t queue_id,
+	__rte_unused struct rte_mbuf *pkts[], uint16_t nb_pkts,
+	__rte_unused uint16_t max_pkts, __rte_unused void *user_param)
+{
+	if (unlikely(nb_pkts == 0)) {
+		if (!itt_rx_data[port_id].queue_state[queue_id]) {
+			__itt_task_begin(
+				itt_rx_data[port_id].domains[queue_id],
+				__itt_null, __itt_null,
+				itt_rx_data[port_id].handles[queue_id]);
+			itt_rx_data[port_id].queue_state[queue_id] = 1;
+		}
+	} else {
+		if (unlikely(itt_rx_data[port_id].queue_state[queue_id])) {
+			__itt_task_end(
+				itt_rx_data[port_id].domains[queue_id]);
+			itt_rx_data[port_id].queue_state[queue_id] = 0;
+		}
+	}
+	return nb_pkts;
+}
+
+/**
+ * Initialization of itt_profile_rx_data for a given Ethernet device.
+ * This function must be invoked when ethernet device is being configured.
+ * Result will be stored in the global array *itt_rx_data*.
+ *
+ * @param port_id
+ *  The port identifier of the Ethernet device.
+ * @param port_name
+ *  The name of the Ethernet device.
+ * @param rx_queue_num
+ *  The number of RX queues on specified port.
+ */
+static inline void
+itt_profile_rx_init(uint8_t port_id, char *port_name, uint8_t rx_queue_num)
+{
+	uint16_t q_id;
+
+	for (q_id = 0; q_id < rx_queue_num; ++q_id) {
+		char domain_name[ITT_MAX_NAME_LEN];
+
+		snprintf(domain_name, sizeof(domain_name),
+			"RXBurst.WastedIterations.Port_%s.Queue_%d",
+			port_name, q_id);
+		itt_rx_data[port_id].domains[q_id]
+			= __itt_domain_create(domain_name);
+
+		char task_name[ITT_MAX_NAME_LEN];
+
+		snprintf(task_name, sizeof(task_name),
+			"port id: %d; queue id: %d",
+			port_id, q_id);
+		itt_rx_data[port_id].handles[q_id]
+			= __itt_string_handle_create(task_name);
+
+		itt_rx_data[port_id].queue_state[q_id] = 0;
+
+		rte_eth_add_rx_callback(
+			port_id, q_id, collect_itt_rx_burst_cb, NULL);
+	}
+}
+#endif /* RTE_ETHDEV_PROFILE_ITT_WASTED_RX_ITERATIONS */
+
+void
+rte_eth_profile_rx_init(__rte_unused uint8_t port_id,
+	__rte_unused struct rte_eth_dev *dev)
+{
+#ifdef RTE_ETHDEV_PROFILE_ITT_WASTED_RX_ITERATIONS
+	itt_profile_rx_init(port_id, dev->data->name, dev->data->nb_rx_queues);
+#endif
+}
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
--- /dev/null
+++ b/lib/librte_ether/rte_ethdev_profile.h
@@ -0,0 +1,52 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_ETHDEV_PROFILE_H_
+#define _RTE_ETHDEV_PROFILE_H_
+
+#include "rte_ethdev.h"
+
+/**
+ * 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);
+
+#endif
-- 
2.7.4


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