{"action":"created","issue":{"url":"https://api.github.com/repos/weaveworks/weave/issues/1438","labels_url":"https://api.github.com/repos/weaveworks/weave/issues/1438/labels{/name}","comments_url":"https://api.github.com/repos/weaveworks/weave/issues/1438/comments","events_url":"https://api.github.com/repos/weaveworks/weave/issues/1438/events","html_url":"https://github.com/weaveworks/weave/pull/1438","id":106593310,"number":1438,"title":"Fast datapath","user":{"login":"dpw","id":15074,"avatar_url":"https://avatars.githubusercontent.com/u/15074?v=3","gravatar_id":"","url":"https://api.github.com/users/dpw","html_url":"https://github.com/dpw","followers_url":"https://api.github.com/users/dpw/followers","following_url":"https://api.github.com/users/dpw/following{/other_user}","gists_url":"https://api.github.com/users/dpw/gists{/gist_id}","starred_url":"https://api.github.com/users/dpw/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dpw/subscriptions","organizations_url":"https://api.github.com/users/dpw/orgs","repos_url":"https://api.github.com/users/dpw/repos","events_url":"https://api.github.com/users/dpw/events{/privacy}","received_events_url":"https://api.github.com/users/dpw/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":{"login":"awh","id":1504438,"avatar_url":"https://avatars.githubusercontent.com/u/1504438?v=3","gravatar_id":"","url":"https://api.github.com/users/awh","html_url":"https://github.com/awh","followers_url":"https://api.github.com/users/awh/followers","following_url":"https://api.github.com/users/awh/following{/other_user}","gists_url":"https://api.github.com/users/awh/gists{/gist_id}","starred_url":"https://api.github.com/users/awh/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/awh/subscriptions","organizations_url":"https://api.github.com/users/awh/orgs","repos_url":"https://api.github.com/users/awh/repos","events_url":"https://api.github.com/users/awh/events{/privacy}","received_events_url":"https://api.github.com/users/awh/received_events","type":"User","site_admin":false},"milestone":null,"comments":8,"created_at":"2015-09-15T16:23:44Z","updated_at":"2015-09-18T11:45:16Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/weaveworks/weave/pulls/1438","html_url":"https://github.com/weaveworks/weave/pull/1438","diff_url":"https://github.com/weaveworks/weave/pull/1438.diff","patch_url":"https://github.com/weaveworks/weave/pull/1438.patch"},"body":"Smoke tests pass (modulo the one that is broken on master), so I think this is fit for a review pass.\r\n\r\nThings still to do:\r\n\r\n* The `weave` script changes are still a bit grotty.  But...\r\n* I think there needs to be a \"disable it all\" option to weave, which disables fastdp, `--net=host`, and the MTU change.\r\n* I haven't modified architecture.txt. To be honest, most of the contents are more like implementation notes that belong as comments in the code.  If the fast datapath code requires additional notes of that nature, I'd be happy to add them as comments. A high-level overview of fast datapath would be a good thing, but I think I'll need to re-write the whole of architecture.txt to match.\r\n* 1.1 compatibility support.  That will be a separate issue.  Short ids is the tricky part here.\r\n* I need to check out a kernel oops I saw when testing with ubuntu 12.04 a few days ago."},"comment":{"url":"https://api.github.com/repos/weaveworks/weave/issues/comments/141425690","html_url":"https://github.com/weaveworks/weave/pull/1438#issuecomment-141425690","issue_url":"https://api.github.com/repos/weaveworks/weave/issues/1438","id":141425690,"user":{"login":"awh","id":1504438,"avatar_url":"https://avatars.githubusercontent.com/u/1504438?v=3","gravatar_id":"","url":"https://api.github.com/users/awh","html_url":"https://github.com/awh","followers_url":"https://api.github.com/users/awh/followers","following_url":"https://api.github.com/users/awh/following{/other_user}","gists_url":"https://api.github.com/users/awh/gists{/gist_id}","starred_url":"https://api.github.com/users/awh/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/awh/subscriptions","organizations_url":"https://api.github.com/users/awh/orgs","repos_url":"https://api.github.com/users/awh/repos","events_url":"https://api.github.com/users/awh/events{/privacy}","received_events_url":"https://api.github.com/users/awh/received_events","type":"User","site_admin":false},"created_at":"2015-09-18T11:45:16Z","updated_at":"2015-09-18T11:45:16Z","body":">>> What functional additions are there to test?\r\n\r\n>> Fallback behaviour.\r\n\r\n> Already there: test/105_frag_2_test.sh\r\n\r\nYou're going to have to help me out - that test isn't modified in the PR, and I can't see how the current version tests fallback. Here's what I think will happen:\r\n\r\n* Both forwarders will race to establish. They will both succeed, but because fdp is preferred it will end up as the 'best' forwarder and the overlay forwarder will be stopped (probably before it completes PMTU discovery)\r\n* The large ping will get fragmented according to the overlay MTU, and as the VXLAN path is unaffected by the iptables rule it will succeed\r\n\r\nWhat am I missing?\r\n"}}