From: Vincent JARDIN <vincent.jardin@6wind.com>
To: Thomas Graf <tgraf@redhat.com>
Cc: "dev@openvswitch.org" <dev@openvswitch.org>,
dev@dpdk.org, Gerald Rogers <gerald.rogers@intel.com>,
dpdk-ovs@ml01.01.org
Subject: Re: [dpdk-dev] [ovs-dev] [PATCH RFC] dpif-netdev: Add support Intel DPDK based ports.
Date: Wed, 29 Jan 2014 11:26:58 +0100 [thread overview]
Message-ID: <52E8D772.9070302@6wind.com> (raw)
In-Reply-To: <52E8B88A.1070104@redhat.com>
Hi Thomas,
On 29/01/2014 09:15, Thomas Graf wrote:
> The obvious and usual best practise would be for DPDK to guarantee
> ABI stability between minor releases.
>
> Since dpdk-dev is copied as well, any comments?
DPDK's ABIs are not Kernel's ABIs, they are not POSIX, there is no
standard. Currently, there is no such plan to have a stable ABI since we
need to keep freedom to chase CPU cycles over having a stable ABI. For
instance, some applications on top of the DPDK process the packets in
less than 150 CPU cycles (have a look at testpmd:
http://dpdk.org/browse/dpdk/tree/app/test-pmd )
I agree that some areas could be improved since they are not into the
critical datapath of packets, but still other areas remain very CPU
constraints. For instance:
http://dpdk.org/browse/dpdk/commit/lib/librte_ether/rte_ethdev.h?id=c3d0564cf0f00c3c9a61cf72bd4bd1c441740637
is bad:
struct eth_dev_ops
is churned, no comment, and a #ifdef that changes the structure
according to compilation!
Should an application use the librte libraries of the DPDK:
- you can use RTE_VERSION and RTE_VERSION_NUM :
http://dpdk.org/doc/api/rte__version_8h.html#a8775053b0f721b9fa0457494cfbb7ed9
- you can write your own wrapper (with CPU overhead) in order to have
a stable ABI, that wrapper should be tight to the versions of the librte
=> the overhead is part of your application instead of the DPDK,
- *otherwise recompile your software, it is opensource, what's the
issue?*
We are opened to any suggestion to have stable ABI, but it should never
remove the options to have fast/efficient/compilation/CPU execution
processing.
Best regards,
Vincent
next prev parent reply other threads:[~2014-01-29 10:25 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-28 1:48 [dpdk-dev] " pshelar
[not found] ` <20140128044950.GA4545@nicira.com>
2014-01-28 5:28 ` [dpdk-dev] [ovs-dev] " Pravin Shelar
2014-01-28 14:47 ` [dpdk-dev] " Vincent JARDIN
2014-01-28 17:56 ` Pravin Shelar
2014-01-29 0:15 ` Vincent JARDIN
2014-01-29 19:32 ` Pravin Shelar
[not found] ` <52E7D2A8.400@redhat.com>
2014-01-28 18:20 ` [dpdk-dev] [ovs-dev] " Pravin Shelar
[not found] ` <52E7D13B.9020404@redhat.com>
2014-01-28 18:17 ` Pravin Shelar
2014-01-29 8:15 ` Thomas Graf
2014-01-29 10:26 ` Vincent JARDIN [this message]
2014-01-29 11:14 ` Thomas Graf
2014-01-29 16:34 ` Vincent JARDIN
2014-01-29 17:14 ` Thomas Graf
2014-01-29 18:42 ` Stephen Hemminger
2014-01-29 20:47 ` François-Frédéric Ozog
2014-01-29 23:15 ` Thomas Graf
2014-03-13 7:37 ` David Nyström
2014-01-29 8:56 ` [dpdk-dev] " Prashant Upadhyaya
2014-01-29 21:29 ` Pravin Shelar
2014-01-30 10:15 ` Prashant Upadhyaya
2014-01-30 16:27 ` Rogers, Gerald
2014-01-29 10:01 ` [dpdk-dev] [ovs-dev] " Thomas Graf
2014-01-29 21:49 ` Pravin Shelar
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