Pádraig Brady <p...@draigbrady.com> writes: > On 11/09/2025 00:31, Collin Funk wrote: >> Pádraig Brady <p...@draigbrady.com> writes: >> >>> This is useful to give better test coverage at least, >>> and may be useful for users who already may have >>> GLIBC_TUNABLES defined to tune their environment, >>> avoiding CPU throttling for example. > >> Probably worth documenting this behavior. >> Although it is hard to imagine that many people use the glibc.cpu >> tunables to disable capabilities that their hardware supports, one might >> be surprised that Coreutils checks them unless it is documented. > > I might do a "Hardware acceleration" section in the texinfo that > documents the supported accelerations in cksum, wc, sha*sum etc, > the configure options (--with-linux-crypto, --with-openssl). > I could also mention there the honored env vars.
That sounds like a good idea to me. >> Also, worth mentioning that the OpenSSL implementations of digests won't >> respect this. > OpenSSL has its own settings (OPENSSL_ia32cap): > > $ truncate -s1G file.big > > $ time cksum -a sha1 file.big > real 0m1.362s > > $ export OPENSSL_ia32cap="0x0" # Disable all CPU features > $ time cksum -a sha1 file.big > real 0m1.942s I did not know about this, thanks. Probably a good argument for the new documentation section you mentioned earlier. Collin
