Online Developer Meeting (2022-05-24)

• Date: Tuesday, May 24, 2022 @ 18:00 UTC
• Location: https://meet.jit.si/octave-dev

Today's topics

• The potential use of Jitter and other virtual machines to speed up Octave execution, by Mohammad-Reza Nabipoor.
  • Discourse thread
  • Unfortunately the speaker didn't show. jwe presented his ideas on VM and linear evaluation instead.
• Drop "native" MXE Octave builders from buildbot configuration?
  • Discourse thread
    • Drop the builder from the buildbot configuration.
    • Don't actively remove support for native builds from MXE Octave. But don't spend too much time maintaining it. Maybe at some later time, someone will step up to maintain it again.
• Timeframe for Octave 7.2 release?
  • Important fixes (among others possible loss of .m file content on exit)
  • still unresolved: bug #62308 use of octave::feval causes error: function '...' not found
    • jwe will create a RC within two weeks
• Update on Fosshost?
  • Buildbot worker on ARM hardware?
    • No, see below
    • Maybe, at a later point ask again for access to their AARCH64 server farm.
  • Possible to run a Mercurial server? With mirror(?), forks for GSoC students(?), ...
    • Possible, needs setup 😇
    • For the time being, GSoC students should use a public service for their fork.
  • Short summary: Octave got one x86_64 server instance (2 cores, 4 GB memory, 500 GB HDD), useful as webserver probably?!

$ uname -a
Linux fosshost 5.10.0-14-amd64 #1 SMP Debian 5.10.113-1 (2022-04-29) x86_64 GNU/Linux

$ free -h
               total
Mem:           3.8Gi

$ lsblk 
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   64G  0 disk 
├─sda1   8:1    0   63G  0 part /
├─sda2   8:2    0    1K  0 part 
└─sda5   8:5    0  975M  0 part [SWAP]
sdb      8:16   0  500G  0 disk 
sr0     11:0    1  378M  0 rom 

$ cat /proc/cpuinfo   # two cores
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 6
model name      : Common KVM processor
stepping        : 1
microcode       : 0x1
cpu MHz         : 2400.084
cache size      : 16384 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx lm constant_tsc nopl xtopology cpuid tsc_known_freq pni cx16 x2apic hypervisor lahf_lm cpuid_fault pti
bugs            : cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs itlb_multihit
bogomips        : 4800.16
clflush size    : 64
cache_alignment : 128
address sizes   : 40 bits physical, 48 bits virtual
power management:

• Access by Arun, jwe, Kai, anyone with time and interest (or ideas what to do with it) is welcome to help with the setup.
  • Kai thinks this could be a webserver, however, what is the benefit to the current situation? 😓
  • See jwe's note here about potential use cases. Moving hg and buildbot from Digital Ocean to Fosshost

Kai will start moving the wiki to FossHost; all web-services should move there eventually

• State of __unimplemented__
  • https://octave.discourse.group/t/implementing-unimplemented-m/2706/5
  • Need clarity about the purpose: Helping search vs. Motivate to join Octave community.
• How to implement a classdef class in C++ code only?
  • Why is the classdef implementation so complicated? Does it need to be?
  • @carandraug and @Maged will look into this for their GSoC project. Pointers welcome.
  • Maybe, some kind of documentation could be a result of the GSoC project.

Previous topics

• Meet and greet 5 minutes before meeting (audio testing).

• Performance over time (Arun, Rik)
  • Discourse thread for background
  • Analysis and profiling of existing code base -- share and solicit experiences.
  • Performance benchmark to track speed over time as part of CI? (Not as part of CI for now, can be done separately, Arun will share progress updates on Discourse)

• GSoC: call for mentors (Nir/Kai)
  • Interesting mentors should write to Nir or Kai before: 2022-05-06, ideally before.
  • Final deadline (to the sponsor) is May 12.

• Octave 7.1.0 post-release remarks:
  • Overall time from merge of default to stable (2021-11-24) until release of version 7.1.0 (2022-04-06): approx. 4 months
    • Why does it take us so long for the last couple of releases?
    • Should we start the release process earlier?
  • A couple of bugs have been solved on the stable branch since the release. Last time we released 6.2.0 pretty early after 6.1.0. Should we do the same again?
  • Regressions that should probably be solved before a potential 7.2.0:
    • bug #62308: use of octave::feval causes error: function '...' not found
    • patch #10200: wrong axes using stairs in subplot --- This affects a lot more plotting functions besides stairs. They always plot into gca and ignore the input axes handle.
    • others?

• Wikipedia updates - minor updates needed to bring up to date.
  • see https://octave.discourse.group/t/octave-wikipedia-pages/2600/1

See also

• Next meeting: Online Developer Meeting (2022-06-28)
• Last meeting: Online Developer Meeting (2022-04-26)