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* [dpdk-dev] [PATCH 0/3] eal: Add new API for threading
@ 2021-03-18  1:00 Narcisa Ana Maria Vasile
  2021-03-18  1:00 ` [dpdk-dev] [PATCH 1/3] Add EAL threads API Narcisa Ana Maria Vasile
                   ` (2 more replies)
  0 siblings, 3 replies; 174+ messages in thread
From: Narcisa Ana Maria Vasile @ 2021-03-18  1:00 UTC (permalink / raw)
  To: dev, thomas, dmitry.kozliuk, khot, navasile, dmitrym, roretzla, ocardona
  Cc: bruce.richardson, david.marchand, pallavi.kadam

From: Narcisa Vasile <navasile@microsoft.com>

EAL thread API

**Problem Statement**
DPDK currently uses the pthread interface to create and manage threads.
Windows does not support the POSIX thread programming model, so it currently
relies on a header file that hides the Windows calls under
pthread API. Given that EAL should isolate the environment
specifics from the applications and libraries and intermediate
the communication with the operating systems, a new EAL interface
is needed for thread management.

**Goals**
* Introduce a generic EAL API for threading support that will remove
  the current Windows pthread.h shim.
* Replace references to pthread_* across the DPDK codebase with the new
  rte_thread_* API.
* Allow users to choose between using the rte_thread_* API or a
  3rd party thread library through a configuration option.

**Design plan**
New API main files:
* rte_thread.h (librte_eal/include)
* rte_thread_types.h (librte_eal/include)
* rte_thread_windows_types.h (librte_eal/windows/include)
* rte_thread.c (librte_eal/windows)
* rte_thread.c (librte_eal/common)

For flexibility, the user is offered the option of either using the rte_thread_* API or
a 3rd party thread library, through a meson flag “use_external_thread_lib”.
By default, this flag is set to FALSE, which means Windows libraries and applications
will use the rte_thread_* API for managing threads.

If compiling on Windows and the new EAL API will be used,
the following files will be parsed: 
* include/rte_thread.h
* windows/include/rte_thread_windows_types.h
* windows/rte_thread.c
In all other cases, the compilation/parsing includes the following files:
* include/rte_thread.h 
* include/rte_thread_types.h
* common/rte_thread.c

**A schematic example of the design**
--------------------------------------------------
lib/librte_eal/include/rte_thread.h
int rte_thread_create();

lib/librte_eal/common/rte_thread.c
int rte_thread_create() 
{
	return pthread_create();
}

lib/librte_eal/windows/rte_thread.c
int rte_thread_create() 
{
	return CreateThread();
}

lib/librte_eal/windows/meson.build
if get_option('use_external_thread_lib')
	sources += 'librte_eal/common/rte_thread.c'
else
	sources += 'librte_eal/windows/rte_thread.c'
endif
-----------------------------------------------------

**Thread attributes**

When or after a thread is created, specific characteristics of the thread
can be adjusted. Given that the thread characteristics that are of interest
for DPDK applications are affinity and priority, the following structure
that represents thread attributes has been defined:

typedef struct
{
	enum rte_thread_priority priority;
	rte_cpuset_t cpuset;
} rte_thread_attr_t;

The *rte_thread_create()* function can optionally receive an rte_thread_attr_t
object that will cause the thread to be created with the affinity and priority
described by the attributes object. If no rte_thread_attr_t is passed
(parameter is NULL), the default affinity and priority are used.
An rte_thread_attr_t object can also be set to the default values
by calling *rte_thread_attr_init()*.

*Priority* is represented through an enum that currently advertises
two values for priority:
	- RTE_THREAD_PRIORITY_NORMAL
	- RTE_THREAD_PRIORITY_REALTIME_CRITICAL
The enum can be extended to allow for multiple priority levels.
rte_thread_set_priority      - sets the priority of a thread
rte_thread_attr_set_priority - updates an rte_thread_attr_t object
                               with a new value for priority

The user can choose thread priority through an EAL parameter,
when starting an application. The two options above are available:

 --thread-prio normal
 --thread-prio realtime
 
Example:
./dpdk-l2fwd -l 0-3 -n 4 –thread-prio normal -- -q 8 -p ffff

*Affinity* is described by the already known “rte_cpuset_t” type.
rte_thread_attr_set/get_affinity - sets/gets the affinity field in a
                                   rte_thread_attr_t object
rte_thread_set/get_affinity      – sets/gets the affinity of a thread

**Errors**
A translation function that maps Windows error codes to errno-style error codes is provided. 

**Future work**
Note that this patchset was focused on introducing new API that will
remove the Windows pthread.h shim. In DPDK, there are still a few references
to pthread_* that were not implemented in the shim.
The long term plan is for EAL to provide full threading support:
* Adding support for conditional variables
* Additional functionality offered by pthread_* (such as pthread_setname_np, etc.)
* Static mutex initializers are not used on Windows. If we must continue using them,
  they need to be platform dependent and an implementation will need to be provided for Windows.

Narcisa Vasile (3):
  Add EAL threads API
  Add EAL argument for setting thread priority
  Enable the new EAL thread API and rename

 app/test/process.h                            |   6 +-
 app/test/test_lcores.c                        |  16 +-
 app/test/test_link_bonding.c                  |  10 +-
 app/test/test_lpm_perf.c                      |  12 +-
 config/meson.build                            |   4 +
 drivers/bus/dpaa/base/qbman/bman_driver.c     |   4 +-
 drivers/bus/dpaa/base/qbman/dpaa_sys.c        |  14 +-
 drivers/bus/dpaa/base/qbman/process.c         |   6 +-
 drivers/bus/fslmc/portal/dpaa2_hw_dpio.c      |   4 +-
 drivers/compress/mlx5/mlx5_compress.c         |  10 +-
 drivers/event/dlb/pf/base/dlb_osdep.h         |   2 +-
 drivers/event/dlb2/pf/base/dlb2_osdep.h       |   2 +-
 drivers/net/af_xdp/rte_eth_af_xdp.c           |  18 +-
 drivers/net/ark/ark_ethdev.c                  |   4 +-
 drivers/net/atlantic/atl_ethdev.c             |   4 +-
 drivers/net/atlantic/atl_types.h              |   5 +-
 .../net/atlantic/hw_atl/hw_atl_utils_fw2x.c   |  24 +-
 drivers/net/axgbe/axgbe_dev.c                 |   8 +-
 drivers/net/axgbe/axgbe_ethdev.c              |   8 +-
 drivers/net/axgbe/axgbe_ethdev.h              |   8 +-
 drivers/net/axgbe/axgbe_i2c.c                 |   4 +-
 drivers/net/axgbe/axgbe_mdio.c                |   8 +-
 drivers/net/axgbe/axgbe_phy_impl.c            |   6 +-
 drivers/net/bnxt/bnxt.h                       |  16 +-
 drivers/net/bnxt/bnxt_cpr.c                   |   4 +-
 drivers/net/bnxt/bnxt_ethdev.c                |  54 +-
 drivers/net/bnxt/bnxt_irq.c                   |   8 +-
 drivers/net/bnxt/bnxt_reps.c                  |  10 +-
 drivers/net/bnxt/tf_ulp/bnxt_ulp.c            |  34 +-
 drivers/net/bnxt/tf_ulp/bnxt_ulp.h            |   4 +-
 drivers/net/bnxt/tf_ulp/ulp_fc_mgr.c          |  24 +-
 drivers/net/bnxt/tf_ulp/ulp_fc_mgr.h          |   2 +-
 drivers/net/ena/base/ena_plat_dpdk.h          |   8 +-
 drivers/net/enic/enic.h                       |   2 +-
 drivers/net/hns3/hns3_ethdev.h                |   2 +-
 drivers/net/hns3/hns3_ethdev_vf.c             |   2 +-
 drivers/net/hns3/hns3_mbx.c                   |   2 +-
 drivers/net/ice/ice_dcf_parent.c              |   4 +-
 drivers/net/ipn3ke/ipn3ke_representor.c       |   6 +-
 drivers/net/ixgbe/ixgbe_ethdev.c              |   2 +-
 drivers/net/ixgbe/ixgbe_ethdev.h              |   2 +-
 drivers/net/kni/rte_eth_kni.c                 |   6 +-
 drivers/net/mlx5/linux/mlx5_os.c              |   2 +-
 drivers/net/mlx5/mlx5.c                       |  20 +-
 drivers/net/mlx5/mlx5.h                       |   2 +-
 drivers/net/mlx5/mlx5_txpp.c                  |   8 +-
 drivers/net/mlx5/windows/mlx5_flow_os.c       |  10 +-
 drivers/net/mlx5/windows/mlx5_os.c            |   2 +-
 drivers/net/qede/base/bcm_osal.h              |   8 +-
 drivers/net/vhost/rte_eth_vhost.c             |  22 +-
 .../net/virtio/virtio_user/virtio_user_dev.c  |  30 +-
 .../net/virtio/virtio_user/virtio_user_dev.h  |   2 +-
 drivers/raw/ifpga/ifpga_rawdev.c              |   8 +-
 drivers/vdpa/ifc/ifcvf_vdpa.c                 |  36 +-
 drivers/vdpa/mlx5/mlx5_vdpa.c                 |  24 +-
 drivers/vdpa/mlx5/mlx5_vdpa.h                 |   6 +-
 drivers/vdpa/mlx5/mlx5_vdpa_event.c           |  54 +-
 examples/kni/main.c                           |   4 +-
 examples/vhost/main.c                         |   2 +-
 examples/vhost_blk/vhost_blk.c                |  10 +-
 lib/librte_eal/common/eal_common_options.c    |  32 +-
 lib/librte_eal/common/eal_common_proc.c       |  48 +-
 lib/librte_eal/common/eal_common_thread.c     |  47 +-
 lib/librte_eal/common/eal_common_trace.c      |   2 +-
 lib/librte_eal/common/eal_internal_cfg.h      |   2 +
 lib/librte_eal/common/eal_options.h           |   2 +
 lib/librte_eal/common/eal_private.h           |   2 +-
 lib/librte_eal/common/malloc_mp.c             |  32 +-
 lib/librte_eal/common/meson.build             |   1 +
 lib/librte_eal/common/rte_thread.c            | 346 ++++++++++++
 lib/librte_eal/freebsd/eal.c                  |  33 +-
 lib/librte_eal/freebsd/eal_alarm.c            |  12 +-
 lib/librte_eal/freebsd/eal_interrupts.c       |   4 +-
 lib/librte_eal/freebsd/eal_thread.c           |   8 +-
 lib/librte_eal/include/rte_lcore.h            |   8 +-
 lib/librte_eal/include/rte_per_lcore.h        |   2 -
 lib/librte_eal/include/rte_thread.h           | 323 ++++++++++-
 lib/librte_eal/include/rte_thread_types.h     |  20 +
 lib/librte_eal/linux/eal.c                    |  36 +-
 lib/librte_eal/linux/eal_alarm.c              |   8 +-
 lib/librte_eal/linux/eal_interrupts.c         |   4 +-
 lib/librte_eal/linux/eal_thread.c             |   8 +-
 lib/librte_eal/linux/eal_timer.c              |   2 +-
 lib/librte_eal/rte_eal_exports.def            |  19 +
 lib/librte_eal/unix/meson.build               |   1 -
 lib/librte_eal/unix/rte_thread.c              |  86 ---
 lib/librte_eal/version.map                    |  21 +
 lib/librte_eal/windows/eal.c                  |  24 +-
 lib/librte_eal/windows/eal_interrupts.c       |   6 +-
 lib/librte_eal/windows/eal_lcore.c            | 167 ++++--
 lib/librte_eal/windows/eal_thread.c           |  24 +-
 lib/librte_eal/windows/eal_windows.h          |  20 +-
 lib/librte_eal/windows/include/meson.build    |   1 +
 lib/librte_eal/windows/include/pthread.h      | 186 -------
 .../include/rte_windows_thread_types.h        |  19 +
 lib/librte_eal/windows/include/sched.h        |   2 +-
 lib/librte_eal/windows/meson.build            |   7 +-
 lib/librte_eal/windows/rte_thread.c           | 507 +++++++++++++++++-
 lib/librte_ethdev/rte_ethdev.c                |   4 +-
 lib/librte_ethdev/rte_ethdev_core.h           |   3 +-
 lib/librte_ethdev/rte_flow.c                  |   4 +-
 .../rte_event_eth_rx_adapter.c                |   6 +-
 lib/librte_vhost/fd_man.c                     |  40 +-
 lib/librte_vhost/fd_man.h                     |   6 +-
 lib/librte_vhost/socket.c                     | 124 ++---
 lib/librte_vhost/vhost.c                      |  10 +-
 meson_options.txt                             |   2 +
 107 files changed, 2001 insertions(+), 899 deletions(-)
 create mode 100644 lib/librte_eal/common/rte_thread.c
 create mode 100644 lib/librte_eal/include/rte_thread_types.h
 delete mode 100644 lib/librte_eal/unix/rte_thread.c
 delete mode 100644 lib/librte_eal/windows/include/pthread.h
 create mode 100644 lib/librte_eal/windows/include/rte_windows_thread_types.h

-- 
2.30.0.vfs.0.2


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