On Wednesday, March 25, 2020 7:09:04 AM CET tu...@posteo.de wrote: > Hi, > > the hardware consists of: > AMD Ryzen 5 3600 > MSI Tomahawk MAX > 32GB RAM (Corsair Venegeance 2x16GB,dual channel) > NVidia RTX 2060 SUPER > > cat /proc/mtrr gives me > > reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back > reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back > reg02: base=0x0c0000000 ( 3072MB), size= 512MB, count=1: write-back > reg03: base=0x0dc0a0000 ( 3520MB), size= 64KB, count=1: uncachable > > -> there is a chunk of uncachable memory > > I activated the sanitizer in the kernel and in kernel I found > this: > > > [ 0.000000] MTRR default type: uncachable > [ 0.000000] MTRR fixed ranges enabled: > [ 0.000000] 00000-9FFFF write-back > [ 0.000000] A0000-BFFFF write-through > [ 0.000000] C0000-FFFFF write-protect > [ 0.000000] MTRR variable ranges enabled: > [ 0.000000] 0 base 000000000000 mask FFFF80000000 write-back > [ 0.000000] 1 base 000080000000 mask FFFFC0000000 write-back > [ 0.000000] 2 base 0000C0000000 mask FFFFE0000000 write-back > [ 0.000000] 3 base 0000DC0A0000 mask FFFFFFFF0000 uncachable > [ 0.000000] 4 disabled > [ 0.000000] 5 disabled > [ 0.000000] 6 disabled > [ 0.000000] 7 disabled > ... > [ 0.000000] gran_size: 64K chunk_size: 64M num_reg: 4 lose cover > RAM: 0G > > So I set the kernel cmdline to: > BOOT_IMAGE=/vmlinuz-5051101-64-RT root=/dev/sda11 ro console=tty0 > console=ttyS0,115200n8 enable_mtrr_cleanup mtrr_spare_reg_nr=1 > mtrr_gran_size=64K mtrr_chunk_size=64M > > rebooted and found the same problem unchanged. > > The Gentoo docs says, that there is a BIOS setting - probably under > "CPU" - which I should set from continuos to separated...but nowaday > BIOSse may look like a part of a Science Fiction moview...but I can > find those setting neither under "EZ" (for "easy settings" not under > "advanced" (for "danger ahead - you may screw up your board"). > > The bios of the board is not the top newest...it is the previous > version. > The changelog of the newest BIOS does not mention anything I would > see as related to the mtrr problem... > > Background: The RTX 2060 SUPER was intended to replace the > old GTX 960 I had....but the "BMW27" benchmark with Blender > is slower than with the GTX 960... > > How can I fix the mtrr problem (and the performance problem > of the graphics card, is related) ? > > Thanks a lot in advance for any help! > Cheers! > Meino
According to the following, MTRR is being phased out in favor of PAT: https://www.kernel.org/doc/html/latest/x86/mtrr.html Something that looks more promising: https://forums.funtoo.org/topic/1865-properly-configuring-mtrr/ Sorry I can't help more, never looked into this myself, but will probably when I do manage to find the time. If you figure it out, please let me know.