On 04.11.2019 17:21, Flavio Leitner wrote:
Hi Ilya,
On Fri, 1 Nov 2019 13:06:33 +0100
Ilya Maximets <[email protected]> wrote:
The conventional way for packet dumping in OVS is to use ovs-tcpdump
that works via traffic mirroring. DPDK pdump could probably be used
for some lower level debugging, but it is not commonly used for
various reasons.
There are lots of limitations for using this functionality in
practice. Most of them connected with running secondary pdump process
and memory layout issues like requirement to disable ASLR in kernel.
More details are available in DPDK guide:
https://doc.dpdk.org/guides/prog_guide/multi_proc_support.html#multi-process-limitations
Beside the functional limitations it's also hard to use this
functionality correctly. User must be sure that OVS and pdump utility
are running on different CPU cores, which is hard because non-PMD
threads could float over available CPU cores. This or any other
misconfiguration will likely lead to crash of the pdump utility
or/and OVS.
Another problem is that the user must actually have this special pdump
utility in a system and it might be not available in distributions.
This change disables pdump support by default introducing special
configuration option '--enable-dpdk-pdump'. Deprecation warnings will
be shown to users on configuration and in runtime.
The deprecation idea sounds good to me, but I don't see a reason to
break the existing behavior if we are going to remove that later on.
Wouldn't just the deprecation notice for next release be sufficient
and then we remove in the after release?
I just thought that it might be unnecessary to put warnings in logs for
users who doesn't care about pdump support. Hiding the feature under
configuration option I made deprecation warning visible to only those
users who enabled it explicitly, i.e. wants to use it.
Do you think it's better to print warnings for everyone?
Best regards, Ilya Maximets.
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