From: DJ Delorie <dj@redhat.com>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: libc-alpha@sourceware.org
Subject: Re: tunables vs osxsave vs checkpointing vs _dl_runtime_resolve
Date: Fri, 19 Mar 2021 17:12:33 -0400 [thread overview]
Message-ID: <xna6qyn8zi.fsf@rhel8.vm> (raw)
In-Reply-To: <20210319164334.GA3876@arm.com> (message from Szabolcs Nagy on Fri, 19 Mar 2021 16:43:35 +0000)
Szabolcs Nagy <szabolcs.nagy@arm.com> writes:
> so are we supposed to handle migrations to machines with
> different arch extensions?
No, that's not the intent. There's a lot of "caveat user" in what our
customer wants, and if the x86 tunables didn't already *almost* do what
they wanted, we would have just said no. I mean, x86 has code to do
what our customer wants, and has code to let tunables control it, it
just didn't actually work. So in this case, it's more of a bug fix than
a new feature.
> cpu_features based decisions can break across different
> machines and there is no reliable (future proof) way to
> request baseline arch features.
That's a separate problem, which we've solved with ifuncs, but others
solve with multilibs. X86 chooses to let tunables override ifunc
choices, and exposes CPU features, setting an expectation. If other
arches don't do that, so be it.
prev parent reply other threads:[~2021-03-19 21:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 17:18 DJ Delorie
2021-03-18 17:29 ` H.J. Lu
2021-03-18 17:45 ` DJ Delorie
2021-03-18 20:39 ` H.J. Lu
2021-03-19 3:40 ` DJ Delorie
2021-03-19 4:16 ` H.J. Lu
2021-03-19 4:35 ` DJ Delorie
2021-03-18 17:32 ` Florian Weimer
2021-03-18 17:47 ` DJ Delorie
2021-03-18 17:57 ` Florian Weimer
2021-03-18 18:19 ` DJ Delorie
2021-03-19 16:43 ` Szabolcs Nagy
2021-03-19 21:12 ` DJ Delorie [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=xna6qyn8zi.fsf@rhel8.vm \
--to=dj@redhat.com \
--cc=libc-alpha@sourceware.org \
--cc=szabolcs.nagy@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).