Compile for Neoverse N1 on Linaro's Armv8 bots that are on Mt Jade hardware #354
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…hardware
This reflects the host hardware, rather than the limited subset of features
on the Cortex-A57.
```
$ lscpu
Architecture: aarch64
CPU op-mode(s): 32-bit, 64-bit
<...>
Vendor ID: ARM
Model name: Neoverse-N1
<...>
Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid
asimdrdm lrcpc dcpop asimddp
```
I have also confirmed that the Neoverse V1 (Note: V not N) that is
used for Graviton is a superset of these features.
https://github.com/aws/aws-graviton-getting-started/blob/main/c-c%2B%2B.md#enabling-arm-architecture-specific-features
So if we have to move these builds to Graviton 3 or 4 at short notice,
the existing configuration will work.
DavidSpickett
requested review from
omjavaid,
leandron and
luporl
and removed request for
leandron
|
Requested / inspired by @omjavaid in a previous review. We do have single stage bots on Mt Jade, but we do not set a specific CPU. I tested these settings by doing a 2 stage build including flang and mlir. With check-all and test suite for both stages, found no problems. |
omjavaid
reviewed
Jan 13, 2025
|
Yes, I was a bit hesitant because the Neoverse N1 isn't a typical AArch32 host, but we have other Armv7 bots with a much earlier CPU setting to cover that side of things. I will just check that there are no new bugs with neoverse-n1 on Armv8. |
DavidSpickett
changed the title
Done. There are v7 builds running on Neoverse-N1 but it makes sense to leave them targeting CPUs that are actually v7, even if they are going to ultimately run on Armv8. |
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This reflects the host hardware, rather than the limited subset of features on the Cortex-A57.
I have also confirmed that the Neoverse V1 (Note: V not N) that is used for Graviton is a superset of these features.
https://github.com/aws/aws-graviton-getting-started/blob/main/c-c%2B%2B.md#enabling-arm-architecture-specific-features
So if we have to move these builds to Graviton 3 at short notice, this will still work (Graviton 4 also ok for AArch64, but it drops the AArch32 mode).