{"thread":{"id":"40606","subject":"Poor git write performance to NFS","startedAt":"2015-10-21T13:14:59Z","lastAt":"2015-10-22T16:11:08Z","messageCount":5,"participants":["Daniel Steinborn","Junio C Hamano","Jeff King"],"isPatch":false,"patchVersion":null,"patchTotal":null},"messages":[{"id":"272032","messageId":"56278FD3.3010103@lrz.de","threadId":"40606","inReplyTo":null,"subject":"Poor git write performance to NFS","fromName":"Daniel Steinborn","fromEmail":"daniel.steinborn@lrz.de","sentAt":"2015-10-21T13:14:59Z","receivedAt":"2015-10-21T13:14:59Z","isPatch":false,"sender":{"key":"daniel.steinborn@lrz.de","avatar":null},"body":"Hi,\n\ncurrently we are experiencing poor write performance when a repository \nis pushed to a nfs volume. Interestingly, this seems to be a problem in \nnewer git versions:\n\nv1.7.12.4: Very good performance\n\nv2.1.4: Bad performance, up to 6 times slower\n\nAre there any changed default settings or new features that can be the \nreason for that problem?\n\nThe tests are done on a Debian 8.2 VM.\n\nPlease ask for specific details if they are neccessary.\n\nThanks for your help! Best regards, Daniel Steinborn\n\n-- \nDaniel Steinborn\nLeibniz-Rechenzentrum\nBoltzmannstraße 1\n85748 Garching bei München\n"},{"id":"272047","messageId":"xmqqlhaw5bj2.fsf@gitster.mtv.corp.google.com","threadId":"40606","inReplyTo":"56278FD3.3010103@lrz.de","subject":"Re: Poor git write performance to NFS","fromName":"Junio C Hamano","fromEmail":"gitster@pobox.com","sentAt":"2015-10-21T18:20:17Z","receivedAt":"2015-10-21T18:20:17Z","isPatch":false,"sender":{"key":"gitster@pobox.com","avatar":"https://avatars.githubusercontent.com/u/54884?v=4"},"body":"Daniel Steinborn writes:\n\n> currently we are experiencing poor write performance when a repository\n> is pushed to a nfs volume. Interestingly, this seems to be a problem\n> in newer git versions:\n>\n> v1.7.12.4: Very good performance\n>\n> v2.1.4: Bad performance, up to 6 times slower\n>\n> Are there any changed default settings or new features that can be the\n> reason for that problem?\n>\n> Please ask for specific details if they are neccessary.\n\nBetween 1.7.12.x series and v2.1.4, there are more than two years'\nworth of changes, so it is unreasonable for anybody to expect that\nsuch a question can be answered in a meaningful way.\n\nHave you tried more recent versions yet? 2.1.x series is over a\nyear old, and I am reasonably sure there have been tons of \"earlier\nwe did X for correctness, which unfortunately made things slower,\nand this ensures the same correctness in a different way that is\nmuch more performant\" fixes since then.\n"},{"id":"272098","messageId":"5628DED0.3050002@lrz.de","threadId":"40606","inReplyTo":"xmqqlhaw5bj2.fsf@gitster.mtv.corp.google.com","subject":"Re: Poor git write performance to NFS","fromName":"Daniel Steinborn","fromEmail":"daniel.steinborn@lrz.de","sentAt":"2015-10-22T13:04:16Z","receivedAt":"2015-10-22T13:04:16Z","isPatch":false,"sender":{"key":"daniel.steinborn@lrz.de","avatar":null},"body":"Hi,\n\nthank you for your answer.\nI removed the git Debian package and compiled v2.6.2 manually. The \nperformance is much better now (on the same level als v1.7.12.4).\nWe opened a Debian bug report, to request a git version >= 2.6 to be \nbackported to jessie: \nhttps://bugs.debian.org/cgi-bin/bugreport.cgi?bug=802661\n\nThe issue is now solved for us, thanks again for your quick response.\n\nBest regards,\nDaniel Steinborn\n\nAm 21.10.2015 um 20:20 schrieb Junio C Hamano:\n> Daniel Steinborn writes:\n>\n>> currently we are experiencing poor write performance when a repository\n>> is pushed to a nfs volume. Interestingly, this seems to be a problem\n>> in newer git versions:\n>>\n>> v1.7.12.4: Very good performance\n>>\n>> v2.1.4: Bad performance, up to 6 times slower\n>>\n>> Are there any changed default settings or new features that can be the\n>> reason for that problem?\n>>\n>> Please ask for specific details if they are neccessary.\n> Between 1.7.12.x series and v2.1.4, there are more than two years'\n> worth of changes, so it is unreasonable for anybody to expect that\n> such a question can be answered in a meaningful way.\n>\n> Have you tried more recent versions yet? 2.1.x series is over a\n> year old, and I am reasonably sure there have been tons of \"earlier\n> we did X for correctness, which unfortunately made things slower,\n> and this ensures the same correctness in a different way that is\n> much more performant\" fixes since then.\n\n-- \nDaniel Steinborn\nLeibniz-Rechenzentrum\nBoltzmannstraße 1\n85748 Garching bei München\n"},{"id":"272105","messageId":"xmqqbnbqubsh.fsf@gitster.mtv.corp.google.com","threadId":"40606","inReplyTo":"5628DED0.3050002@lrz.de","subject":"Re: Poor git write performance to NFS","fromName":"Junio C Hamano","fromEmail":"gitster@pobox.com","sentAt":"2015-10-22T16:07:42Z","receivedAt":"2015-10-22T16:07:42Z","isPatch":false,"sender":{"key":"gitster@pobox.com","avatar":"https://avatars.githubusercontent.com/u/54884?v=4"},"body":"Daniel Steinborn writes:\n\n> I removed the git Debian package and compiled v2.6.2 manually. The\n> performance is much better now (on the same level als v1.7.12.4).\n\nThanks. It is good that we must have done something good within the\npast 12 months between v2.1 and v2.6, even though it feels somewhat\nunsatisfactory not knowing exactly what that good thing is ;-)\n"},{"id":"272106","messageId":"20151022161108.GA10917@sigill.intra.peff.net","threadId":"40606","inReplyTo":"xmqqbnbqubsh.fsf@gitster.mtv.corp.google.com","subject":"Re: Poor git write performance to NFS","fromName":"Jeff King","fromEmail":"peff@peff.net","sentAt":"2015-10-22T16:11:08Z","receivedAt":"2015-10-22T16:11:08Z","isPatch":false,"sender":{"key":"peff@peff.net","avatar":"https://avatars.githubusercontent.com/u/45925?v=4"},"body":"On Thu, Oct 22, 2015 at 09:07:42AM -0700, Junio C Hamano wrote:\n\n> Daniel Steinborn writes:\n> \n> > I removed the git Debian package and compiled v2.6.2 manually. The\n> > performance is much better now (on the same level als v1.7.12.4).\n> \n> Thanks. It is good that we must have done something good within the\n> past 12 months between v2.1 and v2.6, even though it feels somewhat\n> unsatisfactory not knowing exactly what that good thing is ;-)\n\nIt was almost certainly the commits pulled in by e3b199a (Merge branch\n'jk/prune-mtime', 2015-05-05).\n\nAnd 0eeb077 (index-pack: avoid excessive re-reading of pack\ndirectory, 2015-06-09) helps for certain commands, too.\n\n-Peff\n"}]}