Sunday, May 03

Geek

Daily News Stuff 3 May 2020

Your Sourcier Source For Newsier News Edition

Tech News

  • Akane (new server) is nearly three times faster than Aoi (old server) even when Aoi is cheating by using the Psyco JIT compiler.

    Psyco helps a lot in optimising loops and function calls - it's 20x faster on a benchmark that just loops and makes empty function calls - but can't speed up the Python code for functions like string manipulation.  Akane wins by close to 6x on string scanning.

    That's a lot more than the single-threaded difference between a Xeon E3-1230 and a Ryzen 3700X, so it's either a difference in cache sizes (8M vs. 32M) or virtualisation overheads.  Aoi is stuck running OpenVZ within KVM, where Akane is running LXD.

    I'll run the benchmark under PyPy, but I'll need to excise one of the tests.  I test large string concatenations because that's how Minx builds HTML.  That's very fast in Python (and Psyco) but offers nothing but pain and suffering under PyPy due to changes in the garbage collection.


  • I mention LXD and LXC a lot, which might be a bit confusing.  LXC is the container framework, and LXD is a management tool for LXC.  So when you are using LXD, the containers are LXC containers and you mostly use the lxc command to manage them.

    If you are using LXC directly you don't use the lxc command because that's part of LXD.  Instead you use commands like lxc-launch where LXD uses lxc launch.  And if you get the two mixed up you can scramble your configuration.

    Clear?

    Good.

    I miss OpenVZ 6.


  • Also, the ASRock IPMI interface on their Ryzen server boards works.

    One of the long-standing problems with accessing IPMI over long distances (like Australia to the US) is keybounce on the KVM console.  I've often run into cases where it's all but unusable.  No sign of it here.  Ping times aren't wonderful, but it works regardless.

    This means that I can experiment safely with the network config on Akane to get LXD just the way I want it.


  • No we don't.  (Tech Crunch)


  • Nvidia's Hopper architecture may be headed for Samsung's 5nm process or it may not.  (WCCFTech)

    This is supposedly the next generation after Ampere, which is the next generation.

    Interesting point from the table is that the current top of the line Tesla V100 chip is larger than the estimated size of the rumoured 128 CU Navi part.  Whether AMD is working on such a chip is still unknown, but TSMC is capable of manufacturing it if they are.


  • A new California law requires that default passwords be unique for each unit manufactured.  (Serve the Home)

    The password is on the service tag.

    The service tag is on the server.

    The server is in a rack, in a datacenter, 10,000 miles away, and it's 3AM there.

    Which is not to say this law is a bad idea, for all that it came out of the Global Bad Law Research and Development Center in Sacramento.  But sysadmins will have occasion to curse, vehemently, in coming months.


  • There needs to be a Kickstarter for network documentation for LXD BECAUSE THERE FUCKING ISN'T ANY.

    There's a specific command, lxc network, to manage LXD networks, and there's no documentation for it at all, not even a man page.

    This is super painful when you are guessing your way to a solution because any time you screw up there's a good chance you'll lose access to your server.  Which is why I was testing IPMI today.

    Also, if you spin up an Ubuntu virtual machine rather than a container, it comes up with no working networking - and without the standard net-tools installed.  And you can't install net-tools because you have no networking to reach the install repo.  There is still the ip command but that is a pain in the butt.


Video of the Day

Speaking of benchmarks, Steve here speaks of problems of getting equal results over a wide range of systems, when individual CPUs could have anything from 2 to 64 cores.  He mentions one case that turned out to be nothing but a cache size test.  Irrespective of core counts and clock speeds, results were ordered by cache size.




Disclaimer: The one thing worse than network administration is network administration without an administration back-channel.  Though Google managed to break their own back-channel recently, so even that won't always save you.

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