Topics

1

General OpenPOWER Discussion / POWER9 and Hardware Assisted Garbage Collection

« on: August 21, 2023, 09:54:10 pm »

Does anyone know what happened to the Hardware Assisted Garbage Collection feature that was supposed to be in the POWER9 CPUs?  It is in the v3.0 spec, but  not v3.0B so the documentation was removed, but I can't find any mention of the removal.  It's also mentioned in the news from around the time of its release.  I'm guessing that it just didn't make it in to the final silicon for some reason, but I'd love to know if there was ever a reason given.

2

General CPU Discussion / Asymmetric CPUs with the Same Core Count

« on: September 18, 2022, 09:35:19 pm »

I recently saw https://github.com/rigtorp/c2clat and ran it on my dual 18-core machine and got an interesting result.  I've attached an image of it, and the part that seems strange is the bottom left quadrant next to the origin where the pattern doesn't match what's in the top right quadrant.  It reminded me that I had earlier looked at my CPU caches and one seemed to have more than the other.

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compared to

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Does anyone else have asymmetric CPUs with the same core count?  For people with 18-core CPUs, what cache configuration do you have?

3

Talos II / CPU Throttling

« on: September 01, 2022, 05:35:34 pm »

Sometimes when my Talos II is under sustained heavy load I'll get the following messages in dmesg and then my CPUs won't throttle up and my fans are stuck at full power.  Has anyone else run into this or does anyone know how to reset this?  Currently I have to restart to get things back to normal.


[14289.353665] powernv-cpufreq: Pstate set to safe frequency
[14289.353673] powernv-cpufreq: PMSR = 6363631440000000
[14289.353677] powernv-cpufreq: CPU Frequency could be throttled

4

Talos II / WX5100 Causing System Hangs

« on: November 11, 2020, 08:06:51 pm »

I've recently started having problems with my Talos II and WX5100.  Sometimes when I left my system on overnight and tried to turn the screen on in the morning it wouldn't turn on.  It started happening more and more frequently and it seemed to be tied to the card being put into a low power state, so I tried disabling DPMS.  That seemed to work for a little while but now it's back to hanging regularly.  I've attached the console output from  one of the hangs.  When it does hang things still work sometimes except that restarting hangs when it tries kill X and sometimes other processes like Thunderbird or Firefox.

Has anyone else seen this or does anyone have any idea of what the problem might be?  I'm currently running Ubuntu 20.10 with 5.8.0-26-generic and I was originally running Fedora, but I don't remember which kernel versions I tried.