3rd-party/linux-kernel-module-cheat
1
0
Fork 0
mirror of https://github.com/cirosantilli/linux-kernel-module-cheat.git synced 2026-01-25 19:21:35 +01:00
Code Issues Releases Wiki Activity

gem5: integrate fs_bigLITTLE.py into run

Browse Source
This commit is contained in:
Ciro Santilli
2018-06-17 12:05:00 +01:00
parent 57dbe81f33
commit 18c1c823fe
4 changed files with 112 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
README.adoc
View File

@@ -6390,9 +6390,9 @@ The out of build tree is required, because otherwise Buildroot would copy the ou
=== gem5 fs_bigLITTLE
TODO integrate into `run`. There is no way to pass command line arguments except by hacking the script, this is a pre-requisite for good integration.
By default, we use `configs/example/fs.py` script.
This system is more representative of ARM, which almost always has the big little cluster.
The `-X-b` option enables the alternative `configs/example/arm/fs_bigLITTLE.py` script instead.
First apply:
@@ -6418,14 +6418,20 @@ index 7d66c03a6..d71e714fe 100644
then:
....
./fs-biglittle
./run -aA -g -X-b
....
Source: link:fs-biglittle[]
Advantages over `fs.py`:
Boot messages start at 5 minutes, boot finishes at 10 minutes and gives a shell.
* more representative of mobile ARM SoCs, which almost always have big little cluster
* simpler than `fs.py`, and therefore easier to understand and modify
`cat /proc/cpuinfo` shows 4 identical CPUs instead of 2 of two different types, likely because gem5 does not expose some informational register much like the caches: https://www.mail-archive.com/gem5-users@gem5.org/msg15426.html `config.ini` does show that the two big ones are `DerivO3CPU` and the small ones are `MinorCPU`.
Disadvantages over `fs.py`:
* only works for ARM, not other archs
* not as many configuration options as `fs.py`, many things are hardcoded
We setup 2 big and 2 small CPUs, but `cat /proc/cpuinfo` shows 4 identical CPUs instead of 2 of two different types, likely because gem5 does not expose some informational register much like the caches: https://www.mail-archive.com/gem5-users@gem5.org/msg15426.html `config.ini` does show that the two big ones are `DerivO3CPU` and the small ones are `MinorCPU`.
TODO: why is the `--dtb` required despite `fs_bigLITTLE.py` having a DTB generation capability? Without it, nothing shows on terminal, and the simulation terminates with `simulate() limit reached @ 18446744073709551615`. The magic `vmlinux.vexpress_gem5_v1.20170616` works however without a DTB.