By: dmcq (dmcq.delete@this.fano.co.uk), August 21, 2022 11:36 am
Room: Moderated Discussions
Kara (karaardalan.delete@this.gmail.com) on August 20, 2022 11:04 pm wrote:
> rwessel (rwessel.delete@this.yahoo.com) on August 20, 2022 6:50 pm wrote:
> > HTM on about the only platform on which it's been reasonably
> > successfully implemented, namely Z, is going away.
> >
> > On page 93 of:
> >
> > https://www.redbooks.ibm.com/redpieces/pdfs/sg248951.pdf
> >
> > "Removal of support of the transactional execution and constrained transactional
> > execution facility: In a future IBM Z hardware system family, the transactional execution
> > and constrained transactional execution facility will no longer be supported. Users of the
> > facility on current servers should always check the facility indications before use."
> >
> > So introduced on the EC12s, and still on z16, but not long for this world.
> >
> > IBM also removed it from Power10 a couple of years ago.
>
>
> Well, ARM is just getting started with its TME lol.
>
> Also I remember in anandtech's deep dive of the M1 they said apple is using
> a HTM to share threads between the big cores, so, that's something!
Yes I was more than a little surprised about ARM talking about transactional memory when launching ARMv9. They did clean up their memory model when they found problems investigating it a few years ago but I think they must have got to the stage where they believe they can actually implement a reasonable version? Perhaps IBM have discovered a problem like ARM did? Or maybe they've had a better idea? Or is implementing it just too costly overall?
> rwessel (rwessel.delete@this.yahoo.com) on August 20, 2022 6:50 pm wrote:
> > HTM on about the only platform on which it's been reasonably
> > successfully implemented, namely Z, is going away.
> >
> > On page 93 of:
> >
> > https://www.redbooks.ibm.com/redpieces/pdfs/sg248951.pdf
> >
> > "Removal of support of the transactional execution and constrained transactional
> > execution facility: In a future IBM Z hardware system family, the transactional execution
> > and constrained transactional execution facility will no longer be supported. Users of the
> > facility on current servers should always check the facility indications before use."
> >
> > So introduced on the EC12s, and still on z16, but not long for this world.
> >
> > IBM also removed it from Power10 a couple of years ago.
>
>
> Well, ARM is just getting started with its TME lol.
>
> Also I remember in anandtech's deep dive of the M1 they said apple is using
> a HTM to share threads between the big cores, so, that's something!
Yes I was more than a little surprised about ARM talking about transactional memory when launching ARMv9. They did clean up their memory model when they found problems investigating it a few years ago but I think they must have got to the stage where they believe they can actually implement a reasonable version? Perhaps IBM have discovered a problem like ARM did? Or maybe they've had a better idea? Or is implementing it just too costly overall?