From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 09A60A3295 for ; Wed, 23 Oct 2019 12:21:45 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id A61771BFFD; Wed, 23 Oct 2019 12:21:44 +0200 (CEST) Received: from proxy.6wind.com (host.76.145.23.62.rev.coltfrance.com [62.23.145.76]) by dpdk.org (Postfix) with ESMTP id A8CEF1BFF5 for ; Wed, 23 Oct 2019 12:21:43 +0200 (CEST) Received: from glumotte.dev.6wind.com (unknown [10.16.0.195]) by proxy.6wind.com (Postfix) with ESMTP id 922533356C8; Wed, 23 Oct 2019 12:21:43 +0200 (CEST) Date: Wed, 23 Oct 2019 12:21:43 +0200 From: Olivier Matz To: "Wang, Haiyue" Cc: "Ananyev, Konstantin" , "dev@dpdk.org" , Andrew Rybchenko , "Richardson, Bruce" , Jerin Jacob Kollanukkaran , "Wiles, Keith" , Morten =?iso-8859-1?Q?Br=F8rup?= , Stephen Hemminger , Thomas Monjalon Message-ID: <20191023102143.GI25286@glumotte.dev.6wind.com> References: <20190710092907.5565-1-olivier.matz@6wind.com> <20191017144219.32708-1-olivier.matz@6wind.com> <2601191342CEEE43887BDE71AB97725801A8C6E2BD@IRSMSX104.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [dpdk-dev] [PATCH v2] mbuf: support dynamic fields and flags X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Wed, Oct 23, 2019 at 03:16:13AM +0000, Wang, Haiyue wrote: > > -----Original Message----- > > From: Ananyev, Konstantin > > Sent: Wednesday, October 23, 2019 06:52 > > To: Olivier Matz ; dev@dpdk.org > > Cc: Andrew Rybchenko ; Richardson, Bruce ; Wang, > > Haiyue ; Jerin Jacob Kollanukkaran ; Wiles, Keith > > ; Morten Brørup ; Stephen Hemminger > > ; Thomas Monjalon > > Subject: RE: [PATCH v2] mbuf: support dynamic fields and flags > > > > > > > Many features require to store data inside the mbuf. As the room in mbuf > > > structure is limited, it is not possible to have a field for each > > > feature. Also, changing fields in the mbuf structure can break the API > > > or ABI. > > > > > > This commit addresses these issues, by enabling the dynamic registration > > > of fields or flags: > > > > > > - a dynamic field is a named area in the rte_mbuf structure, with a > > > given size (>= 1 byte) and alignment constraint. > > > - a dynamic flag is a named bit in the rte_mbuf structure. > > > > > > The typical use case is a PMD that registers space for an offload > > > feature, when the application requests to enable this feature. As > > > the space in mbuf is limited, the space should only be reserved if it > > > is going to be used (i.e when the application explicitly asks for it). > > > > > > The registration can be done at any moment, but it is not possible > > > to unregister fields or flags for now. > > > > > > Signed-off-by: Olivier Matz > > > Acked-by: Thomas Monjalon > > > --- > > > > > > v2 > > > > > > * Rebase on top of master: solve conflict with Stephen's patchset > > > (packet copy) > > > * Add new apis to register a dynamic field/flag at a specific place > > > * Add a dump function (sugg by David) > > > * Enhance field registration function to select the best offset, keeping > > > large aligned zones as much as possible (sugg by Konstantin) > > > * Use a size_t and unsigned int instead of int when relevant > > > (sugg by Konstantin) > > > * Use "uint64_t dynfield1[2]" in mbuf instead of 2 uint64_t fields > > > (sugg by Konstantin) > > > * Remove unused argument in private function (sugg by Konstantin) > > > * Fix and simplify locking (sugg by Konstantin) > > > * Fix minor typo > > > > > > rfc -> v1 > > > > > > * Rebase on top of master > > > * Change registration API to use a structure instead of > > > variables, getting rid of #defines (Stephen's comment) > > > * Update flag registration to use a similar API as fields. > > > * Change max name length from 32 to 64 (sugg. by Thomas) > > > * Enhance API documentation (Haiyue's and Andrew's comments) > > > * Add a debug log at registration > > > * Add some words in release note > > > * Did some performance tests (sugg. by Andrew): > > > On my platform, reading a dynamic field takes ~3 cycles more > > > than a static field, and ~2 cycles more for writing. > > > > > > app/test/test_mbuf.c | 145 ++++++- > > > doc/guides/rel_notes/release_19_11.rst | 7 + > > > lib/librte_mbuf/Makefile | 2 + > > > lib/librte_mbuf/meson.build | 6 +- > > > lib/librte_mbuf/rte_mbuf.h | 23 +- > > > lib/librte_mbuf/rte_mbuf_dyn.c | 548 +++++++++++++++++++++++++ > > > lib/librte_mbuf/rte_mbuf_dyn.h | 226 ++++++++++ > > > lib/librte_mbuf/rte_mbuf_version.map | 7 + > > > 8 files changed, 959 insertions(+), 5 deletions(-) > > > create mode 100644 lib/librte_mbuf/rte_mbuf_dyn.c > > > create mode 100644 lib/librte_mbuf/rte_mbuf_dyn.h > > > > > > diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c > > > index b9c2b2500..01cafad59 100644 > > > --- a/app/test/test_mbuf.c > > > +++ b/app/test/test_mbuf.c > > > @@ -28,6 +28,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > > > [snip] > > > +int > > > +rte_mbuf_dynflag_register_bitnum(const struct rte_mbuf_dynflag *params, > > > + unsigned int req) > > > +{ > > > + int ret; > > > + > > > + if (req != UINT_MAX && req >= 64) { > > > > Might be better to replace 64 with something like sizeof(mbuf->ol_flags) * CHAR_BIT or so. > > Might introduce a new macro like kernel: > > /** > * FIELD_SIZEOF - get the size of a struct's field > * @t: the target struct > * @f: the target struct's field > * Return: the size of @f in the struct definition without having a > * declared instance of @t. > */ > #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) > > Then: FIELD_SIZEOF(rte_mbuf, ol_flags) * CHAR_BIT Good idea, thanks