1 Koji is Fedora's build system
3 http://fedora.riscv.rocks/koji/
4 https://koji.fedoraproject.org/koji/
6 Doesn't use cross-compilation, and not possible with current design.
7 We must find a way to run a full build system somehow.
9 Discussion of primary architecture.
14 ## What hardware should we choose for RISC-V as a primary architecture?
16 * Milk-V Pioneer (SG2042)
17 * Sophgo 2U server (SG2042)
19 - Possible performance and quality issues [unverified]
21 - Likely to end up as e-waste soon.
26 - Doesn't support any recent extensions, esp. V, H
27 - No BMC, but might use BMC-on-PCIe card
29 * [Mystery manufacturer] future development board (under NDA)
31 * Single board computers (SBCs)
33 - VisionFive2 (StarFive JH7xxx), Lichee Pi 4A, ...
35 - Limited memory, cores
37 - Upfront & ongoing engineering headaches integrating into a 19" rack
41 - Performance numbers below, but not great
42 - Really using x86-64 hardware
43 - Hardware (x86-64) is well known and easy to manage
44 - No "e-waste", servers can be repurposed
45 - Supports all the latest extensions
46 - Supports any amount of RAM, large numbers of vCPUs
47 - We can add new extensions and fix bugs relatively easily
54 ## QEMU performance numbers
56 (Times in seconds, taken from recent Fedora Koji builds)
58 binutils openssl python3.12 mingw-gcc
60 i686 1589 1577 3411 4292
62 x86-64 1419 1172 2462 1827
64 aarch64 1573 811 (?) 1845 2521
66 ppc64le 2165 1291 3073 4388
68 s390x 2553 1380 1984 (?) 6824
70 ------------ ------------ ------------ ------------
72 [qemu-system-riscv64 16 cores, 16 GB; on AMD Ryzen 9 7950X server]
75 (LTO) 4493 3052 14502 12428
76 +217% +160% +489% +580%
78 (no LTO) 3267 1351 6353 (failed)
92 "TCG" is the name for QEMU's software emulation, eg. RISC-V fully
93 emulated guest on x86-64 host.
95 Works using Translation Blocks (TBs) which translate basic blocks of
98 Well understood (by me), easy to fix simpler issues.
100 - I posted a patch yesterday which gets ~ +6% performance gain
102 A few tips to make TCG run (a bit) fast(er):
104 - Compile with -march=native (+4%)
108 - Don't overprovision host CPUs
110 * However pinning vCPUs to pCPUs didn't really help
112 - Give it plenty of guest & host RAM
114 * Measured memory overhead on host is up to 40% after running
117 * Host TBs track guest page cache; as long as a translated
118 executable remains in the guest page cache, it will not be
121 - Don't restart the VM