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-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1794957 Title: pipelining on archive.u.c aborts after 101 packages Status in apt package in Ubuntu: Fix Released Status in apt source package in Xenial: Fix Released Status in apt source package in Bionic: Fix Released Bug description: [Impact] Downloading many packages on archive.ubuntu.com or some other mirrors seems to close the connection after every 100 or so packages. APT prior to 1.7.0~rc1 (commit df696650b7a8c58bbd92e0e1619e956f21010a96), treats a connection closure with a 200 response as meaning that the server does not support pipelining, hence disabling it for any further downloads. With high speed connections at higher latency, this can cause a severe reduction in usable bandwidth. For example, I saw speeds drop from 40 MB/s to 15 MB/s due to this. The fix ensures that we continue pipelining if the previous connection to the server successfully retrieved at least 3 files with pipelining enabled. [Test case] Pick a package that would cause a large number (200/300 packages of packages to be installed). I used plasma-desktop and xubuntu-desktop, for example. Run apt install -d $package. Ensure that after the first 101 packages the progress does not slow down - you should not see a lot "working" in the progress output. The speed should be substantially higher. Don't run in a container setup by cloud-init, as cloud-init disables pipelining; or remove /etc/apt/apt.conf.d/90cloud-init-pipelining (see bug 1794982). Requirements: * High speed, medium-high latency connection (e.g. 400 Mbit/s at 30 ms RTT is enough); or just increase latency, e.g. sudo tc qdisc add dev wlp61s0 root netem delay 300ms until you see the slow down * Not a terribly slow CPU, as we'd get slowed down by hashing otherwise [Regression potential] This fix is isolated to code enabling/disabling pipelining on subsequent connections. It could cause more pipelining to be tried on servers who are not particularly good at it, but can deal with 3 items correctly. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1794957/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
