1185GRE i7 Cache Allocation Technology (CAT) Config Problem
Dear Community,
I have multiple systems with Core i7 1185GRE processors on UP Xtreme i11 Series boards, I'm using them for realtime applications, and I have to do optimizations now to go further. A cyclic task jitter is higher than expected and high peaks are happening randomly. I'm using Ubuntu 24.04 / 6.8 realtime kernel currently, TCC and all related parameters set up correctly in the BIOS, kernel parameters also set up correctly. The next thing would be to separate allocate dedicated LLC cache ways for realtime cores.
This guide was really helpful, I followed it thorughout the setup. The documentation is implying that I should be able to customize L3 / LLC cache allocation. But in reality I couldn't find make it work using documentations. The standard tool would be RDT / pqos tools, but pqos only lists L2 level cache, it says that L3 is not settable, it does not list them. I also tried to use msr with no luck, the corresponding addresses couldn't be set.
I understood from this documentation, that on some of the CPU's this is non-architectural, so as of my understanding, standard tools couldn't be used there, so I tried to install TCC Tools
This article is showing the result of setting LLC cache with this CPU family succesfully with an other board, they were using i5 version of this processor, so I suppose it should be done with i7 with no problems.
I tried to use ECI tools, used the (currently) latest v3.3 to generate currently available Ubuntu 22.04 and 24.04 images, tried to install TCC tools using this guide, but the verification step fails,
sudo /usr/share/tcc_tools/scripts/setup_ssram/tcc_setup_ssram.sh enable --verify
I'm using UEFI BIOS, at boot time there is an error "No SSRAM Region found!" and "Start RTCM hypervisor runtime driver failed."
I checked the BIOS settings many times very carefully, but I do not have option in the BIOS called Software-SRAM (SSRAM) or Data Streams Optimizer (DSO), I believe that these are the missing pieces to be able to proceed.
I got stuck, does anybody have some thoughts or experiences on this matter? Is it even possible to do this with this board? Any thoughts would be appreciated.
Many thanks!
Answers
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@polarursus
please flash attached BIOS, it's enabled TCC by default and let me know if there are still any problem, thanks.
