[lowrisc-dev] Support for Fedora / compressed extension

Manuel A. Fernandez Montecelo manuel.montezelo at gmail.com
Mon Apr 2 12:27:55 BST 2018

2018-04-02 09:23 Dr Jonathan Kimmitt:
>Dear Richard,
>My mistake, lowRISC-v0.5 runs a lightweight source based distribution based on RISCV-poky, using our modified 1.9.1 kernel and device drivers which have not been upstreamed. It would be perfectly possible to compile Fedora without compression but this would just move the bottleneck to a different place which is that the emulator is over a hundred times slower than a modern PC, and limited to 128M of RAM. Even running yum takes more than this at times. Swapping is also slow because it relies on individual writes to SD-card with 4 bits @ 5MHz, which itself has internal latency. In addition network access is throttled to about 2 megabytes per second due to TCP stack and bus width considerations.
>With the best will in the world most mainstream distributions have more or less abandoned the embedded market by preferring heavyweight python based system tools which trade off memory for performance (feel free to dispute this sweeping generalisation, I know apt can run on the iPhone).  I am aware of course that Python has many benefits in robustness and foolproofing.

apt is C++, though, and the main source of "memory usage" at runtime
comes from the thousands of packages available in a full-fledged
GNU/Linux distribution.

Not sure in an FPGA, but it runs fine even in spike, AFAICR.

Aside from this... dispute :) I suppose that Richard's question is more
like: will you support the C extension at some point, so lowRISC will be
able to run Fedora/Debian/etc. in the near future?

One doesn't always need to run apt/dnf/yum etc. to be able to use
thousands of packages precompiled.  One can just copy the file and
install with dpkg or rpm for example, which are much less demanding.

Manuel A. Fernandez Montecelo <manuel.montezelo at gmail.com>

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