Topics

16

Talos II / mixing memory sizes on the same CPU?

« on: August 30, 2022, 03:00:09 am »

I understand that each CPU has four memory channels, therefore, optimum performance is achieved when all four memory banks have an identical size and they are accessed in parallel.

Nonetheless, is it safe or practical to mix memory sizes in the memory banks on the same CPU?

For example, could the user have 2 x 16GB and 2 x 32GB connected to a single CPU?

Would the CPU ignore the extra capacity in the larger modules and use them all as 16GB?  Or would it somehow access the RAM using two channel speeds?

17

Talos II / different memory sizes on each CPU in multi-CPU systems?

« on: August 30, 2022, 02:56:21 am »

For dual CPU systems, is it necessary to have an identical memory configuration on each CPU?

For example, if a user has 4 x 16GB on CPU1 does that mean the user must have 4 x 16GB on CPU2?

Or can the user have 4 x 16GB on CPU1 and 4 x 32GB on CPU2?

18

General OpenPOWER Discussion / creating dashboard or heatmap to identify pinch-points in other FOSS projects

« on: August 28, 2022, 01:05:27 am »

This was a comment in the discussion about donating a Blackbird to a worthy cause

It is probably not hard to create a dashboard to scrape or aggregate issues from bug trackers in various free software projects and assemble them into some kind of dashboard or heat map to identify the pinch-points for widespread OpenPOWER use.

Scraping the data is rather easy, most bug trackers have at least one well known API like RSS or iCalendar.

Identifying which issues relate to OpenPOWER depends on how diligent people are in tagging their bugs.

Deciding how to prioritize the issues on a dashboard or heat map may be more contentious as different people have different perspectives about which issues are important.

19

General OpenPOWER Discussion / workaround for using x86-only video-calling and WebRTC applications

« on: August 20, 2022, 04:02:20 am »

Consider the following setup:

main workstation:
- POWER9
- GPU
- OBS
- capture hardware

secondary workstation or laptop
- x86
- untrusted OS (e.g. Windows)
- applications that you are required to run for a client or employer (e.g. a messaging or remote desktop app) or a video meeting system that requires WebAssembly

You can generate an RTP video stream from the workstation, receive it on the secondary workstation and make it available as a virtual webcam for the software on that machine

I opened a couple of discussions about the topic:

http://ffmpeg.org/pipermail/ffmpeg-user/2022-August/055275.html

https://obsproject.com/forum/threads/obs-streaming-udp-to-ffmpeg-to-v4l2-loopback.158367/

20

Operating Systems and Porting / suspend, sleep, hibernate and resume?

« on: July 08, 2022, 08:24:44 am »

I saw a couple of threads with comments that the Raptor systems can't suspend or hibernate, this comment and this comment

I searched the wiki and it didn't have any pages about suspend, sleep, hibernate

Does anybody have more details about this?

In the event that hibernate is really impossible, are there any workarounds that people recommend for restoring desktop to a previous state after a complete shutdown?  For example, I've seen some utilities that can reopen windows on the same workspaces and in the same places but this doesn't solve everything.

21

User Zone / Multi-seat systems (multiple keyboard/mouse/monitor users on one workstation)

« on: June 02, 2022, 08:12:20 am »

There are some hints about multi-seat setups in other topics in the forum

Multi-seat can make the workstations more viable because the cost is shared between two or three users.

I had some discussions about this with a few people.  Most people are satisfied that POWER9 provides enough compute capacity but there were some practical concerns

The type of user who would benefit from this setup is typically a developer, system administrator or IT support worker who already works in Linux

By their nature, this type of user would like to tweak the system, for example, installing some kernel module, installing some non-standard version of some development header files or whatever.

What level of isolation can be achieved between users in such scenarios?

For example, using virtualization, people can have their own kernels and separate GPU ports.

Using LXC and cgroups, people can have their own root filesystem but they share a kernel

Has anybody tested these possibilities with POWER / Linux workstations or even on x86?

I found some links about the topic for some of the distributions that people are using

Hardware passthrough in LXC or running a desktop in a cgroup

two X servers one graphics card

Debian - Multi Seat

Fedora - Multi Seat

Arch - Multi Seat

FreeBSD - Multi Seat

22

GPU Compute / Accelerators / AMD Radeon RX 6800, 6800 XT and 6900 XT status?

« on: April 12, 2022, 04:24:07 am »

Has anybody tried any of these cards with a recent kernel?

Does the kernel command line option mentioned on the wiki here make any difference?

Code: [Select]

amdgpu.aspm=0


23

General Discussion / Areca Tri-mode HBA NVMe / SAS / SATA controllers

« on: October 17, 2021, 05:41:43 am »

Online store / catalog

These are not cheap but they look like interesting HBAs for people who have a lot of disks and want to link them all into their workstation or server through a single x16 slot.

Has anybody tried any of them?

How do they compare to other brands offering a Tri-mode solution?

24

General Discussion / Aplicata Quattro 400 (PCIe 3.0 x8, 4x M.2 NVMe slots, total 8GB/s capacity)

« on: October 17, 2021, 05:37:53 am »

Quattro 400 web page

Has anybody tried it?

It is not really fast enough for somebody who wants the newest SSDs like the Samsung Pro 980, each of those can do 7GB/s.

For previous generation SSDs operating up to 4GB/s this looks like an interesting HBA for software RAID, Btrfs or ZFS in a x8 slot.

25

General Discussion / OWC Shuttle 3.5" with U.2 connector for up to four NVMe SSDs and ShuttleOne 2.5"

« on: October 17, 2021, 04:00:49 am »

OWC Shuttle - four SSDs, 3.5"

OWC Shuttle - one SSD, 2.5"

ZD Net pictures

The model that takes four SSDs may be more interesting for Talos II and Blackbird users

It is part of OWC's set of products for Thunderbolt but it says you can use the Shuttle by itself in any workstation that has U.2 support from a HBA.

Being more verbose, the full system comprises three parts: OWC's external Thunderbolt-to-PCIe case, an SSD carrier module, like a miniature backplane that goes in the case and finally, the Shuttle module itself.  This full system would not be relevant for Talos II / Blackbird as they don't have Thunderbolt ports, nonetheless, the Shuttle by itself may be interesting.

It is not clear how the four M.2 SSDs are combined into a single U.2 port: is this bifurcation, is there some kind of switch chipset or is there something else in the U.2 standard that allows multiple devices to be combined into a single U.2 port?

It says that they support PCIe 4.0 but it is not clear if they support the newest high speed PCIe 4.0 SSDs.

26

General Discussion / Broadcom P411W-32P HBA, PCIe 4.0 x16 for NVMe (U.2, U.3 and M.2) SSDs

« on: October 17, 2021, 03:18:50 am »

Official site

Specifications in PDF

This is a controller for multiple SSDs.  It uses a switch, not bifurcation.  As noted elsewhere, bifurcation is not really supported on Talos II

The specifications and price look interesting for workstation builds where you want to combine 2, 3 or 4 SSDs for a simple RAID-1 mirror with the Linux md RAID, btrfs or ZFS.

The benefit of buying this type of card is that only one PCIe slot is consumed for multiple SSDs.  On the systems with only two slots (Talos II Lite and Blackbird) that is an important consideration.

Specifications in PDF give a lot of detail about support for backplanes, it is not clear if you can simply connect the ports directly to U.2 SSDs using the right cable.

The M.2 SSDs can be mounted in U.2/M.2 carriers.

Has anybody tried it?

27

Firmware / wiki incomplete: checking current System Package/BMC/PNOR/FPGA versions?

« on: October 11, 2021, 02:06:31 pm »

The wiki has a lot of details about how to install firmware but I couldn't see instructions about how to check the currently running firmware version.

Furthermore, Raptor appear to be using "System Package" version numbers to represent some mix of individual packages that have their own distinct version numbers.  For example, the Talos II v2.00 isn't OpenBMC 2.00.  I feel this list would look better as a table showing the Raptor version in one column and other relevant versions in extra columns.  For example, a column for OpenBMC, another for Linux kernel, etc.

Then if you log in and look at the uname output you can take the kernel version and try to deduce which System Package from Raptor you are running.

https://wiki.raptorcs.com/wiki/Talos_II/Firmware

https://wiki.raptorcs.com/wiki/Updating_Firmware

28

Applications and Porting / Firefox WebAssembly (WASM) on ppc64le? Jitsi Meet, Zoom, etc not working

« on: June 16, 2021, 11:04:02 am »

Does anybody know about support for Firefox WebAssembly (WASM) on ppc64le?

Some web sites like Zoom don't work without it.

Since March, it looks like Jitsi Meet may require WebAssembly too

Is WASM available in any recent version of Firefox?  Can it be enabled if I rebuild Firefox from source?

29

Applications and Porting / Eclipse 4.19 crashing at startup on Debian buster

« on: April 14, 2021, 01:03:45 pm »

I took the download of Eclipse for ppc64el and tried it on my system.

It crashes at startup, I opened a bug report with full details, download link, stack trace
https://bugs.eclipse.org/bugs/show_bug.cgi?id=572837

Does it work for anybody else?

To test it:

Code: [Select]

mkdir ~/eclipse-test
cd ~/eclipse-test
wget 'https://download.eclipse.org/eclipse/downloads/drops4/R-4.19-202103031800/download.php?dropFile=eclipse-SDK-4.19-linux-gtk-ppc64le.tar.gz'
tar xzf eclipse-SDK-4.19-linux-gtk-ppc64le.tar.gz
eclipse/eclipse



30

GPU Compute / Accelerators / AMD Radeon RX 6800 / 6900 (Big Navi) sales strategy

« on: March 06, 2021, 11:40:54 am »

It looks like retailers are building combined Ryzen + RX 6800 XT systems with OEM parts and you have to buy the whole system instead of buying the GPU alone.

Has anybody else noticed this trend or been able to get the GPU standalone for a POWER9 system?