[v4,0/8] lib/ring: add zero copy APIs

  It is pretty common for the DPDK applications to be deployed in
semi-pipeline model. In these models, a small number of cores
(typically 1) are designated as I/O cores. The I/O cores work
on receiving and transmitting packets from the NIC and several
packet processing cores. The IO core and the packet processing
cores exchange the packets over a ring. Typically, such applications
receive the mbufs in a temporary array and copy the mbufs on
to the ring. Depending on the requirements the packets
could be copied in batches of 32, 64 etc resulting in 256B,
512B etc memory copy.

The zero copy APIs help avoid intermediate copies by exposing
the space on the ring directly to the application.

v4:
1) Fixed multiple pointer issues
2) Added documentation

v3:
1) Changed the name of the APIs to 'zero-copy (zc)'
2) Made the address calculation simpler
3) Structure to return the data to the user is aligned on
   cache line boundary.
4) Added functional and stress test cases

v2: changed the patch to use the SP-SC and HTS modes

v1: Initial version

Honnappa Nagarahalli (8):
  lib/ring: add zero copy APIs
  test/ring: move common function to header file
  test/ring: add functional tests for zero copy APIs
  test/ring: add stress tests for zero copy APIs
  doc/ring: add zero copy peek APIs
  test/ring: fix the memory dump size
  test/ring: remove unnecessary braces
  test/ring: user uintptr_t instead of unsigned long

 app/test/meson.build                   |   2 +
 app/test/test_ring.c                   | 209 +++++++++-
 app/test/test_ring.h                   |  67 ++-
 app/test/test_ring_mt_peek_stress_zc.c |  56 +++
 app/test/test_ring_st_peek_stress_zc.c |  65 +++
 app/test/test_ring_stress.c            |   6 +
 app/test/test_ring_stress.h            |   2 +
 app/test/test_ring_stress_impl.h       |   2 +-
 doc/guides/prog_guide/ring_lib.rst     |  41 ++
 doc/guides/rel_notes/release_20_11.rst |   9 +
 lib/librte_ring/meson.build            |   1 +
 lib/librte_ring/rte_ring_elem.h        |   1 +
 lib/librte_ring/rte_ring_peek_zc.h     | 546 +++++++++++++++++++++++++
 13 files changed, 988 insertions(+), 19 deletions(-)
 create mode 100644 app/test/test_ring_mt_peek_stress_zc.c
 create mode 100644 app/test/test_ring_st_peek_stress_zc.c
 create mode 100644 lib/librte_ring/rte_ring_peek_zc.h
  

Hi David,
	Checkpatch CI is showing "WARNING" on a lot of the patches in this series, but it does not list any real warnings.  Any idea what is happening?

Thanks,
Honnappa

> -----Original Message-----
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Sent: Saturday, October 24, 2020 11:11 AM
> To: dev@dpdk.org; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; konstantin.ananyev@intel.com;
> stephen@networkplumber.org
> Cc: Dharmik Thakkar <Dharmik.Thakkar@arm.com>; Ruifeng Wang
> <Ruifeng.Wang@arm.com>; olivier.matz@6wind.com;
> david.marchand@redhat.com; nd <nd@arm.com>
> Subject: [PATCH v4 0/8] lib/ring: add zero copy APIs
> 
> It is pretty common for the DPDK applications to be deployed in semi-
> pipeline model. In these models, a small number of cores (typically 1) are
> designated as I/O cores. The I/O cores work on receiving and transmitting
> packets from the NIC and several packet processing cores. The IO core and
> the packet processing cores exchange the packets over a ring. Typically, such
> applications receive the mbufs in a temporary array and copy the mbufs on
> to the ring. Depending on the requirements the packets could be copied in
> batches of 32, 64 etc resulting in 256B, 512B etc memory copy.
> 
> The zero copy APIs help avoid intermediate copies by exposing the space on
> the ring directly to the application.
> 
> v4:
> 1) Fixed multiple pointer issues
> 2) Added documentation
> 
> v3:
> 1) Changed the name of the APIs to 'zero-copy (zc)'
> 2) Made the address calculation simpler
> 3) Structure to return the data to the user is aligned on
>    cache line boundary.
> 4) Added functional and stress test cases
> 
> v2: changed the patch to use the SP-SC and HTS modes
> 
> v1: Initial version
> 
> Honnappa Nagarahalli (8):
>   lib/ring: add zero copy APIs
>   test/ring: move common function to header file
>   test/ring: add functional tests for zero copy APIs
>   test/ring: add stress tests for zero copy APIs
>   doc/ring: add zero copy peek APIs
>   test/ring: fix the memory dump size
>   test/ring: remove unnecessary braces
>   test/ring: user uintptr_t instead of unsigned long
> 
>  app/test/meson.build                   |   2 +
>  app/test/test_ring.c                   | 209 +++++++++-
>  app/test/test_ring.h                   |  67 ++-
>  app/test/test_ring_mt_peek_stress_zc.c |  56 +++
> app/test/test_ring_st_peek_stress_zc.c |  65 +++
>  app/test/test_ring_stress.c            |   6 +
>  app/test/test_ring_stress.h            |   2 +
>  app/test/test_ring_stress_impl.h       |   2 +-
>  doc/guides/prog_guide/ring_lib.rst     |  41 ++
>  doc/guides/rel_notes/release_20_11.rst |   9 +
>  lib/librte_ring/meson.build            |   1 +
>  lib/librte_ring/rte_ring_elem.h        |   1 +
>  lib/librte_ring/rte_ring_peek_zc.h     | 546 +++++++++++++++++++++++++
>  13 files changed, 988 insertions(+), 19 deletions(-)  create mode 100644
> app/test/test_ring_mt_peek_stress_zc.c
>  create mode 100644 app/test/test_ring_st_peek_stress_zc.c
>  create mode 100644 lib/librte_ring/rte_ring_peek_zc.h
> 
> --
> 2.17.1
  

On Sat, Oct 24, 2020 at 6:18 PM Honnappa Nagarahalli
<Honnappa.Nagarahalli@arm.com> wrote:
>
> Hi David,
>         Checkpatch CI is showing "WARNING" on a lot of the patches in this series, but it does not list any real warnings.  Any idea what is happening?

I reported it to Thomas last night.
Thomas has fixed a few things in the script but I don't know if he's
finished with it.
  

25/10/2020 08:16, David Marchand:
> On Sat, Oct 24, 2020 at 6:18 PM Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com> wrote:
> >
> > Hi David,
> >         Checkpatch CI is showing "WARNING" on a lot of the patches in this series, but it does not list any real warnings.  Any idea what is happening?
> 
> I reported it to Thomas last night.
> Thomas has fixed a few things in the script but I don't know if he's
> finished with it.

Yes this is an issue in Linux checkpatch that I've updated on the server
just before you send this series.
Then I've fixed it:

--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -977,7 +977,7 @@ sub seed_camelcase_includes {
 sub git_is_single_file {
        my ($filename) = @_;
 
-       return 0 if ((which("git") eq "") || !(-e "$gitroot"));
+       return 0 if ((which("git") eq "") || !(-e "$root/.git"));