On 13 Nov 2019, at 14:23, Ilya Maximets wrote:
On 13.11.2019 1:21, William Tu wrote:
On Thu, Nov 7, 2019 at 3:36 AM Ilya Maximets <i.maxim...@ovn.org>
wrote:
Until now there was only two options for XDP mode in OVS: SKB or
DRV.
i.e. 'generic XDP' or 'native XDP with zero-copy enabled'.
Devices like 'veth' interfaces in Linux supports native XDP, but
doesn't support zero-copy mode. This case can not be covered by
existing API and we have to use slower generic XDP for such devices.
There are few more issues, e.g. TCP is not supported in generic XDP
mode for veth interfaces due to kernel limitations, however it is
supported in native mode.
This change introduces ability to use native XDP without zero-copy
along with best-effort configuration option that enabled by default.
In best-effort case OVS will sequentially try different modes
starting
from the fastest one and will choose the first acceptable for
current
interface. This will guarantee the best possible performance.
If user will want to choose specific mode, it's still possible by
setting the 'options:xdp-mode'.
This change additionally changes the API by renaming the
configuration
knob from 'xdpmode' to 'xdp-mode' and also renaming the modes
themselves to be more user-friendly.
The full list of currently supported modes:
* native-with-zerocopy - former DRV
* native - new one, DRV without zero-copy
* generic - former SKB
* best-effort - new one, chooses the best available from
3 above modes
Since 'best-effort' is a default mode, users will not need to
explicitely set 'xdp-mode' in most cases.
TCP related tests enabled back in system afxdp testsuite, because
'best-effort' will choose 'native' mode for veth interfaces
and this mode has no issues with TCP.
Signed-off-by: Ilya Maximets <i.maxim...@ovn.org>
---
I'm thinking about adding some tests case and patches depends on
this API change. If there is no more comment, I will apply to master.
I think, it might be good to wait for some comments from Eelco.
@Eelco, do you have a plan to review the code? Do you agree with the
API update?
I’m rather busy this week, will try to review it next week, and I’m
ok with the API change.
The only thing that bothers me is the worse performance of the TAP
interface with the new default config.
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