Messages in this thread | | | Subject | Re: Candidate Linux ABI for Intel AMX and hypothetical new related features | From | "Enrico Weigelt, metux IT consult" <> | Date | Wed, 30 Jun 2021 17:25:12 +0200 |
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On 30.06.21 15:55, Arjan van de Ven wrote:
>> * this feature needs to be initialized first, before it can be used >> * on first use (when not initialized yet), it traps into the kernel >> * we don't want to always initialize it at boot >> >> Correct ? > > not really, the init is PER PROCESS
IIRC there had been some discussion here whether it should be done per thread. But now that I've learned that the major problem is saving the register state, I wouldn't dare thinking about how a working per-thread solution really would need to look like :o
(by the way: is sighandler stack per thread or per process ?)
> the kernel needs to be able to say "no" in a graceful way, there are > several scenarios > (from the sysadmin wanting to manage power/performance/resources to > outright compatibility where > the kernel wants or needs to say "no". Most obvious example: if a > process asked for an sigaltstack, > we can't let the process use AMX since that stack will be too small most > likely to hold > the stackframe)
Ah okay, when I wrote that mail, didn't know yet that so much state needs to be saved.
--mtx
-- --- Hinweis: unverschlüsselte E-Mails können leicht abgehört und manipuliert werden ! Für eine vertrauliche Kommunikation senden Sie bitte ihren GPG/PGP-Schlüssel zu. --- Enrico Weigelt, metux IT consult Free software and Linux embedded engineering info@metux.net -- +49-151-27565287
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