-----Original Message-----
From: dev <dev-boun...@dpdk.org> On Behalf Of Ferruh Yigit
Sent: Wednesday, October 13, 2021 11:16 PM
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Subject: Re: [dpdk-dev] [PATCH v6 0/6] hide eth dev related structures
On 10/13/2021 2:36 PM, Konstantin Ananyev wrote:
v6 changes:
- Update comments (Andrew)
- Move callback related variables under corresponding ifdefs (Andrew)
- Few nits in rte_eth_macaddrs_get (Andrew)
- Rebased on top of next-net tree
v5 changes:
- Fix spelling (Thomas/David)
- Rename internal helper functions (David)
- Reorder patches and update commit messages (Thomas)
- Update comments (Thomas)
- Changed layout in rte_eth_fp_ops, to group functions and
related data based on their functionality:
first 64B line for Rx, second one for Tx.
Didn't observe any real performance difference comparing to
original layout. Though decided to keep a new one, as it seems
a bit more plausible.
v4 changes:
- Fix secondary process attach (Pavan)
- Fix build failure (Ferruh)
- Update lib/ethdev/verion.map (Ferruh)
Note that moving newly added symbols from EXPERIMENTAL to DPDK_22
section makes checkpatch.sh to complain.
v3 changes:
- Changes in public struct naming (Jerin/Haiyue)
- Split patches
- Update docs
- Shamelessly included Andrew's patch:
https://patches.dpdk.org/project/dpdk/patch/20210928154856.1015020-
1-andrew.rybche...@oktetlabs.ru/
into these series.
I have to do similar thing here, so decided to avoid duplicated effort.
The aim of these patch series is to make rte_ethdev core data structures
(rte_eth_dev, rte_eth_dev_data, rte_eth_rxtx_callback, etc.) internal to
DPDK and not visible to the user.
That should allow future possible changes to core ethdev related structures
to be transparent to the user and help to improve ABI/API stability.
Note that current ethdev API is preserved, but it is a formal ABI break.
The work is based on previous discussions at:
https://www.mail-archive.com/dev@dpdk.org/msg211405.html
https://www.mail-archive.com/dev@dpdk.org/msg216685.html
and consists of the following main points:
1. Copy public 'fast' function pointers (rx_pkt_burst(), etc.) and
related data pointer from rte_eth_dev into a separate flat array.
We keep it public to still be able to use inline functions for these
'fast' calls (like rte_eth_rx_burst(), etc.) to avoid/minimize slowdown.
Note that apart from function pointers itself, each element of this
flat array also contains two opaque pointers for each ethdev:
1) a pointer to an array of internal queue data pointers
2) points to array of queue callback data pointers.
Note that exposing this extra information allows us to avoid extra
changes inside PMD level, plus should help to avoid possible
performance degradation.
2. Change implementation of 'fast' inline ethdev functions
(rte_eth_rx_burst(), etc.) to use new public flat array.
While it is an ABI breakage, this change is intended to be transparent
for both users (no changes in user app is required) and PMD developers
(no changes in PMD is required).
One extra note - with new implementation RX/TX callback invocation
will cost one extra function call with this changes. That might cause
some slowdown for code-path with RX/TX callbacks heavily involved.
Hope such trade-off is acceptable for the community.
3. Move rte_eth_dev, rte_eth_dev_data, rte_eth_rxtx_callback and
related
things into internal header: <ethdev_driver.h>.
That approach was selected to:
- Avoid(/minimize) possible performance losses.
- Minimize required changes inside PMDs.
Performance testing results (ICX 2.0GHz, E810 (ice)):
- testpmd macswap fwd mode, plus
a) no RX/TX callbacks:
no actual slowdown observed
b) bpf-load rx 0 0 JM ./dpdk.org/examples/bpf/t3.o:
~2% slowdown
- l3fwd: no actual slowdown observed
Would like to thank everyone who already reviewed and tested previous
versions of these series. All other interested parties please don't be shy
and provide your feedback.
Konstantin Ananyev (6):
ethdev: allocate max space for internal queue array
ethdev: change input parameters for rx_queue_count
ethdev: copy fast-path API into separate structure
ethdev: make fast-path functions to use new flat array
ethdev: add API to retrieve multiple ethernet addresses
ethdev: hide eth dev related structures
For series,
Reviewed-by: Ferruh Yigit <ferruh.yi...@intel.com>
No performance regression detected on my testing.
I am merging the series to next-net now which helps testing,
but before merging to main repo it will be good to get more
ack and test results (I can squash new tags later).
@Jerin, @Ajit, @Raslan, @Andrew, @Qi, @Honnappa,
Can you please test this set for any possible regression?
Series applied to dpdk-next-net/main, thanks.
