From: Nicholas Piggin <npiggin@gmail.com>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [RFC PATCH] powerpc/powernv: Provide a way to force a core into SMT4 mode
Date: Sat, 27 Jan 2018 10:27:35 +1000 [thread overview]
Message-ID: <20180127102735.5075a560@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <20180125050512.GA18744@fergus.ozlabs.ibm.com>
On Thu, 25 Jan 2018 16:05:12 +1100
Paul Mackerras <paulus@ozlabs.org> wrote:
> POWER9 processors up to and including "Nimbus" v2.2 have hardware
> bugs relating to transactional memory and thread reconfiguration.
> One of these bugs has a workaround which is to get the core into
> SMT4 state temporarily. This workaround is only needed when
> running bare-metal.
How often will this be triggered, in practice? If it's infrequent,
then would it be better to just do a smp_call_function on siblings
and get them all spinning there? I'm looking sadly at the added
sync...
Thanks,
Nick
next prev parent reply other threads:[~2018-01-27 0:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 5:05 [RFC PATCH] powerpc/powernv: Provide a way to force a core into SMT4 mode Paul Mackerras
2018-01-27 0:27 ` Nicholas Piggin [this message]
2018-01-27 2:45 ` Paul Mackerras
2018-01-27 4:47 ` Nicholas Piggin
2018-01-27 1:06 ` Ram Pai
2018-01-27 2:34 ` Paul Mackerras
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