Messages in this thread | | | Subject | Re: [RFC v1 1/2] um: drivers: remove support for UML_NET_PCAP | From | Anton Ivanov <> | Date | Tue, 10 Dec 2019 07:08:40 +0000 |
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On 09/12/2019 23:40, Brendan Higgins wrote: > On Sat, Dec 7, 2019 at 1:15 AM Anton Ivanov > <anton.ivanov@cambridgegreys.com> wrote: >> On 07/12/2019 01:21, Brendan Higgins wrote: >>> On Fri, Dec 06, 2019 at 04:32:34PM -0800, Brendan Higgins wrote: >>>> On Thu, Dec 5, 2019 at 11:23 PM Anton Ivanov >>>> <anton.ivanov@cambridgegreys.com> wrote: >>>> [...] >>>>> 1. There is a proposed patch for the build system to fix it. >>> So I just tried the patch you linked on the cover letter[1], and I am >>> still getting the build error described above: >>> >>> arch/um/drivers/pcap_user.c:35:12: error: conflicting types for ‘pcap_open’ >>> static int pcap_open(void *data) >>> ^~~~~~~~~ >>> In file included from /usr/include/pcap.h:43, >>> from arch/um/drivers/pcap_user.c:7: >>> /usr/include/pcap/pcap.h:859:18: note: previous declaration of ‘pcap_open’ was here >>> PCAP_API pcap_t *pcap_open(const char *source, int snaplen, int flags, >>> >>> Looking at the patch, I wouldn't expect it to solve this problem. >>> >>> Are there maybe different conflicting libpcap-dev libraries and I have >>> the wrong one? Or is this just still broken? >>> >>>>> 2. We should be removing all old drivers and replacing them with the >>>>> vector ones. >>>> Hmm...does this mean you would entertain a patch removing all the >>>> non-vector UML network drivers? I would be happy to see VDE go as >>>> well. >>>> >>>> In any event, it sounds like I should probably drop this patch as it >>>> is currently. >>>> >>>> Thanks! >>> [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=938962#79 >>> >>> _______________________________________________ >>> linux-um mailing list >>> linux-um@lists.infradead.org >>> http://lists.infradead.org/mailman/listinfo/linux-um >>> >> OK, looks like the pcap.h differs now as well. >> >> I will fix that too. It looks like you need both a pcap fix and a >> library linking fix for this to work. >> >> The patch fixes the issue with the build system which no longer provides >> the means for UML to specify extra libraries (I probably had an older >> pcap version on the machine where I tested this). >> >> IMHO frankly it is no longer necessary. >> >> 5.5-rc1 vector raw now has the facility to add/remove (including at >> runtime) filters compiled with pcap outside UML. It was merged this week. >> >> We now have the following line-up for vector drivers - EoGRE, EoL2TPv3, >> RAW (+/- BPF), TAP and BESS. Speeds are 2.5 to 9Gbit on my machine >> (mid-range Ryzen desktop). >> >> If I figure out a way to get hold of the underlying tap raw sockets the >> same way vhost does, TAP can probably go to 12Gbit or thereabouts. Same >> applies to getting zerocopy working with raw. >> >> As a basis for comparison I get 18Gbit on the same machine using vEth >> and containers. 50% of that is actually a very decent number. >> >> While vector drivers are not 1:1 replacements for the existing drivers, >> you can achieve the same topologies and the same connectivity at much >> higher performance - the old drivers test out in the 500Mbit range on >> the same hardware. >> >> IMHO we should at least mark them as "obsolete" and start preparing to >> remove them. > Alright, I will send a patch out which marks the other network drivers > as "obsolete". > > Clarification: Should I mark all UML network devices as "obsolete" > except for NET_VECTOR? Daemon and MCAST looked to me (I am not a > networking expert), like they might not be covered by vector. > They are not 1:1 replacements unfortunately.
However, in order to fix daemon I have to rewrite the switch from uml-utilities too. It is beyond obsolete.
MCAST for 2 UML instances can be replaced by either GRE or L2TPv3, for more than 2 you are better off introducing a proper switch.
I am OK if all old drivers are marked as obsolete at this point, so please proceed with the patch.
Brgds,
-- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/
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