It's easy, just run sudo fwupdmgr get-updates followed by sudo fwupdmgr update. The system needs to be on AC power to perform the update.

posted at: 22:07 | path: /configuration | permanent link

It's possible to just list multiple domains in opendkim.conf which will all get signed with the same key indicated by KeyFile and Selector (as pointed out here).

# Sign for example.com with key in /etc/dkimkeys/dkim.key using
# selector 'mail' (e.g. mail._domainkey.example.com)
# hacky, multiple domains, all share the same key and the same DNS setup
# so we also need mail._domainkey.bla.net and mail._domainkey.blub.org DNS records
Domain                  example.com, bla.net, blub.org
KeyFile                 /etc/dkimkeys/example.com.key
Selector                mail

A more complex way with individual mappins is described here.

A good way to test the setup is appmaildev.com's DKIM Test.

posted at: 10:10 | path: /configuration | permanent link

Debian unstable recently updates the PostSRSd to 2.0.11-1+b1, breaking stuff:

1. new postfix configuration required (and pointed out in the NEWS)

     sender_canonical_maps = socketmap:unix:srs:forward
     sender_canonical_classes = envelope_sender
     recipient_canonical_maps = socketmap:unix:srs:reverse
     recipient_canonical_classes = envelope_recipient, header_recipient
   

2. apparmor changes required (or should apparmor be dropped?)

     /etc/postsrsd.conf r,
     /var/spool/postfix/** rwk,
   

posted at: 11:00 | path: /configuration | permanent link

IKEA has some smart home products: Zigbee light bulbs, a temperature sensor, several remote controller, and -- most importantly -- the Dirigera hub which allows to control the devices via an app or REST API. The hub supports the matter standard and lacks technical documentation (it has USB-C for power supply, an Ethernet plug and expects to local network with WiFi). A Python package, dirigera, is available.

First step is to generate a token (JWT) to enable access to the API, which requires pressing the "Action" button on the hub.

posted at: 18:05 | path: /projects | permanent link

We have a significant workload (> 50k CPU hours per year) on AWS EC2 instances running a Windows program. Since Linux instances are cheaper and easier to maintain (think Docker), we tried to get that Windows application running using Wine. A native Linux port is unfortunately not feasible, since the application depends on some closed-source libraries.

Initial benchmarks were not encouraging:

Platform	Runtime
Windows 11	479 s
Linux 6.12	2636 s

Linux/Wine being 5 times slower.

Wine offers nice logging/tracing abilities by setting the environment variable WINEDEBUG=+relay,+heap. This revealed far too many calls to heap allocation functions. Since the application is statically linked against the C runtime, Wine's heap allocation function may be less optimized than the original Windows function or require more overhead. Also perf top points to Wine's heap_allocation_block function.

mimalloc is a general purpose memory allocator with excellent performance. For statically-linked programs, it is possible to override the global C++ new and delete operators by just #including mimalloc-new-delete.h in one source file.

Benchmarks for the same program/workload as above, statically linked with mimalloc:

Platform	Allocator	Runtime	Peak Memory
Windows 11	default	479 s	12.6 GB
Windows 11	mimalloc v3.0.3	438 s	12.2 GB
Windows 11	mimalloc v2.2.3	440 s	12.9 GB
Linux 6.12	default	2636 s	14.3 GB
Linux 6.12	mimalloc v3.0.3	crash	N/A
Linux 6.12	mimalloc v2.2.3	435 s	12.4 GB

Mimalloc v3.0.3 seems to be a tad faster than v2.2.3 and on Windows it reduces runtime by about 10 % and peak memory allocation by about 2 GB. On Linux/Wine, the improvement is dramatic, the runtime is en par (or slightly faster) than on Windows. Note: CPUs were AMD Ryzen 9 5900X and AMD Ryzen 5 5600G on Windows and Linux, resp.

The crash on Linux with mimalloc v3.0.3 is probably related to issue #1087 and due to the new page-map feature having trouble with low addresses of memory allocations (which Wine provides) -- looking forward to a fix!

posted at: 12:46 | path: /programming | permanent link