5630257fcc
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
55 lines
2.4 KiB
ReStructuredText
55 lines
2.4 KiB
ReStructuredText
.. SPDX-License-Identifier: BSD-3-Clause
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Copyright(c) 2017 Intel Corporation.
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Service Cores
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=============
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DPDK has a concept known as service cores, which enables a dynamic way of
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performing work on DPDK lcores. Service core support is built into the EAL, and
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an API is provided to optionally allow applications to control how the service
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cores are used at runtime.
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The service cores concept is built up out of services (components of DPDK that
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require CPU cycles to operate) and service cores (DPDK lcores, tasked with
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running services). The power of the service core concept is that the mapping
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between service cores and services can be configured to abstract away the
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difference between platforms and environments.
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For example, the Eventdev has hardware and software PMDs. Of these the software
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PMD requires an lcore to perform the scheduling operations, while the hardware
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PMD does not. With service cores, the application would not directly notice
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that the scheduling is done in software.
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For detailed information about the service core API, please refer to the docs.
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Service Core Initialization
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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There are two methods to having service cores in a DPDK application, either by
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using the service coremask, or by dynamically adding cores using the API.
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The simpler of the two is to pass the `-s` coremask argument to EAL, which will
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take any cores available in the main DPDK coremask, and if the bits are also set
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in the service coremask the cores become service-cores instead of DPDK
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application lcores.
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Enabling Services on Cores
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~~~~~~~~~~~~~~~~~~~~~~~~~~
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Each registered service can be individually mapped to a service core, or set of
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service cores. Enabling a service on a particular core means that the lcore in
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question will run the service. Disabling that core on the service stops the
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lcore in question from running the service.
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Using this method, it is possible to assign specific workloads to each
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service core, and map N workloads to M number of service cores. Each service
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lcore loops over the services that are enabled for that core, and invokes the
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function to run the service.
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Service Core Statistics
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~~~~~~~~~~~~~~~~~~~~~~~
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The service core library is capable of collecting runtime statistics like number
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of calls to a specific service, and number of cycles used by the service. The
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cycle count collection is dynamically configurable, allowing any application to
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profile the services running on the system at any time.
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