From: Panu Matilainen <pmatilai@redhat.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>, dev@dpdk.org
Cc: huawei.xie@intel.com, Thomas Monjalon <thomas.monjalon@6wind.com>,
Traynor Kevin <kevin.traynor@intel.com>,
Rich Lane <rich.lane@bigswitch.com>,
Tetsuya Mukawa <mukawa@igel.co.jp>
Subject: Re: [dpdk-dev] [PATCH v3 00/20] vhost ABI/API refactoring
Date: Thu, 30 Jun 2016 10:39:45 +0300 [thread overview]
Message-ID: <2add15af-5323-1f0c-b057-e29eeefb94c3@redhat.com> (raw)
In-Reply-To: <1465271530-27878-1-git-send-email-yuanhan.liu@linux.intel.com>
On 06/07/2016 06:51 AM, Yuanhan Liu wrote:
> v3: - adapted the new vhost ABI/API changes to tep_term example, to make
> sure not break build at least.
> - bumped the ABI version to 3
>
> NOTE: I created a branch at dpdk.org [0] for more conveinient testing:
>
> [0]: git://dpdk.org/next/dpdk-next-virtio for-testing
>
>
> Every time we introduce a new feature to vhost, we are likely to break
> ABI. Moreover, some cleanups (such as the one from Ilya to remove vec_buf
> from vhost_virtqueue struct) also break ABI.
>
> This patch set is meant to resolve above issue ultimately, by hiding
> virtio_net structure (as well as few others) internaly, and export the
> virtio_net dev strut to applications by a number, vid, like the way
> kernel exposes an fd to user space.
>
> Back to the patch set, the first part of this set makes some changes to
> vhost example, vhost-pmd and vhost, bit by bit, to remove the dependence
> to "virtio_net" struct. And then do the final change to make the current
> APIs to adapt to using "vid".
>
> After that, "vrtio_net_device_ops" is the only left open struct that an
> application can acces, therefore, it's the only place that might introduce
> potential ABI breakage in future for extension. Hence, I made few more
> (5) space reservation, to make sure we will not break ABI for a long time,
> and hopefuly, forever.
Been intending to say this for a while but seems I never actually got
around to do so:
This is a really fine example of how to refactor an API against constant
ABI breakages, thank you Yuanhan! Exported structs are one of the
biggest obstacles in keeping a stable ABI while adding new features, and
while its not always possible to hide everything to this extent, the
damage (erm, exposure) can usually be considerably limited by careful
API design.
Since the first and the foremost objection against doing this in the
DPDK context is always "but performance!", I'm curious as to what sort
of numbers you're getting with the new API vs the old one? I'm really
hoping other libraries would follow suit after seeing that its possible
to provide a future-proof API/ABI without sacrificing performance :)
Thanks again,
- Panu -
next prev parent reply other threads:[~2016-06-30 7:39 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-02 22:25 [dpdk-dev] [PATCH 00/16] " Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 01/16] vhost: declare backend with int type Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 02/16] vhost: set/reset dev flags internally Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 03/16] vhost: declare device_fh as int Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 04/16] example/vhost: make a copy of virtio device id Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 05/16] vhost: rename device_fh to vid Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 06/16] vhost: get device by vid only Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 07/16] vhost: move vhost_device_ctx to cuse Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 08/16] vhost: query pmd internal by vid Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 09/16] vhost: add few more functions Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 10/16] vhost: export vid as the only interface to applications Yuanhan Liu
2016-05-10 16:17 ` Rich Lane
2016-05-10 16:39 ` Yuanhan Liu
2016-05-10 17:13 ` Rich Lane
2016-05-10 17:29 ` Yuanhan Liu
2016-05-10 19:22 ` Thomas Monjalon
2016-05-02 22:25 ` [dpdk-dev] [PATCH 11/16] vhost: hide internal structs/macros/functions Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 12/16] vhost: remove unnecessary fields Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 13/16] vhost: remove virtio-net.h Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 14/16] vhost: reserve few more space for future extension Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 15/16] vhost: per device vhost_hlen Yuanhan Liu
2016-05-02 22:25 ` [dpdk-dev] [PATCH 16/16] vhost: make buf vector for scatter Rx local Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 00/19] vhost ABI/API refactoring Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 01/19] vhost: declare backend with int type Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 02/19] vhost: set/reset dev flags internally Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 03/19] vhost: declare device fh as int Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 04/19] examples/vhost: make a copy of virtio device id Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 05/19] vhost: rename device fh to vid Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 06/19] vhost: get device by vid only Yuanhan Liu
2016-05-13 5:24 ` [dpdk-dev] [PATCH v2 07/19] vhost: move vhost device ctx to cuse Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 08/19] vhost: introduce new API to export numa node Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 09/19] vhost: introduce new API to export number of queues Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 10/19] vhost: introduce new API to export ifname Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 11/19] vhost: introduce new API to export queue free entries Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 12/19] vhost: remove dependency on priv field Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 13/19] vhost: export vid as the only interface to applications Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 14/19] vhost: hide internal structs/macros/functions Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 15/19] vhost: remove unnecessary fields Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 16/19] vhost: remove virtio-net.h Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 17/19] vhost: reserve few more space for future extension Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 18/19] vhost: per device virtio net header len Yuanhan Liu
2016-05-13 5:25 ` [dpdk-dev] [PATCH v2 19/19] vhost: make buf vector for scatter Rx local Yuanhan Liu
2016-05-26 17:04 ` [dpdk-dev] [PATCH v2 00/19] vhost ABI/API refactoring Rich Lane
2016-05-27 1:36 ` Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 00/20] " Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 01/20] vhost: declare backend with int type Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 02/20] vhost: set/reset dev flags internally Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 03/20] vhost: declare device fh as int Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 04/20] examples/vhost: make a copy of virtio device id Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 05/20] vhost: rename device fh to vid Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 06/20] vhost: get device by vid only Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 07/20] vhost: move vhost device ctx to cuse Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 08/20] vhost: introduce new API to export numa node Yuanhan Liu
2016-06-07 11:42 ` Panu Matilainen
2016-06-07 12:45 ` Yuanhan Liu
2016-06-08 21:51 ` Rich Lane
2016-06-09 4:45 ` Yuanhan Liu
2016-06-13 10:05 ` Yuanhan Liu
2016-06-07 3:51 ` [dpdk-dev] [PATCH v3 09/20] vhost: introduce new API to export number of queues Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 10/20] vhost: introduce new API to export ifname Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 11/20] vhost: introduce new API to export queue free entries Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 12/20] vhost: remove dependency on priv field Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 13/20] vhost: export vid as the only interface to applications Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 14/20] vhost: hide internal structs/macros/functions Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 15/20] vhost: remove unnecessary fields Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 16/20] vhost: remove virtio-net.h Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 17/20] vhost: reserve few more space for future extension Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 18/20] examples/tep_term: adapt to new vhost ABI/API changes Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 19/20] vhost: per device virtio net header len Yuanhan Liu
2016-06-07 3:52 ` [dpdk-dev] [PATCH v3 20/20] vhost: make buf vector for scatter Rx local Yuanhan Liu
2016-06-14 12:00 ` [dpdk-dev] [PATCH v3 00/20] vhost ABI/API refactoring Yuanhan Liu
2016-06-30 7:39 ` Panu Matilainen [this message]
2016-06-30 7:57 ` Yuanhan Liu
2016-06-30 9:05 ` Panu Matilainen
2016-06-30 11:15 ` Mcnamara, John
2016-06-30 11:40 ` Thomas Monjalon
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