Hi Paul and release team,

On 2026-05-26 21:30, Paul Gevers wrote:
> Hi riscv64 porters,
> 
> In bug 1092153 [1] we discussed the slowness of the riscv64 hardware
> available for Debian. At the time we accepted the situation as a
> bootstrapping problem. Recently we've witnessed some delays because of
> riscv64 build speed (e.g. migration delay for linux kernel CVE fixes), and
> since riscv64 got added to ci.debian.net it needed shepherding to stay up
> and a lot of tests actually fail because of the slowness.
> 
> Hence, I'd like to request an update on the situation. When do you think the
> situation can be improved realistically? As an example, I've heard that for
> some of the faster hardware, the kernel patches still aren't accepted
> upstream. Also, on what timescale can the slow hardware (both buildds and
> the ci.d.n hardware) be replaced with faster hardware that runs reliably?

I am answering here about the build daemons part as the debci part has 
already been answered by Bo Yu.

First of all the requirements for the build daemons is a bit more 
challenging than debci, as we want to run them on our own hardware, 
using the Debian (bpo) kernel, in a rack-mountable format. As pointed 
out in bug #1092153, we had identified two possible hardware platforms.  
Unfortunately neither turn out to be suitable for build daemons.  
Complete kernel support for the HiFive Premier P550 is still lacking, 
and we experienced some stability issues with the Milk-V Pioneer.

We therefore looked for alternatives and found the Milk-V Jupiter board 
with a SpacemiT K1 CPU to be a good candidate, with a lot of upstreaming 
work happening. The Debian 7.0 backports kernel is now suitable to run a 
build daemon. Testing shows a performance improvement by a factor of 1.7 
to 2.2, depending on the level of parallelism. For example, the Linux 
kernel can be built in about 9 hours and rustc in about 14 hours. We 
also expect an additional 10% gain once cpufreq support is available, 
as the CPU is currently not running at its nominal speed. In addition 
support for vector instructions may further improve performance for some 
specific packages.

The other option that appeared recently is the SpacemiT K3. The 
upstreaming process is progressing quite fast, also benefiting from the 
existing K1 code. The Debian backports kernel is already able to boot on 
such a machine, but with a quite limited set of devices. Kernel 7.2 or 
7.3 (the 7.2 merge window is not yet fully closed) should provide 
sufficient support for use as a build daemons, so likely around fall. 
Online benchmarks indicate we should expect to halve the build time 
compared to the K1, although we have not yet been able to validate this 
ourselves due to lack of hardware.

Regarding the timescale, we started the process of upgrading the build 
daemons with the Spacemit K1, beginning with MANDA. The first two boards 
arrived there last week and are waiting to be installed. The plan is to 
upgrade the two other boards once we are sure everything is working fine 
with the two first boards.

For OSUOSL, we still have to plan and decide if we go with the K1 or if 
we wait for the K3. That will depends on how things move in the next 
weeks on the K3 side (upstreaming, access to K3 hardware, etc.).

Regards
Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
[email protected]                     http://aurel32.net

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