DD2.3 POWER9 steppings now available
Raptor now has SKUs for the Sforza DD2.3 POWER9 chips, which they're calling "POWER9 v2". Currently just the 4-core and 8-core are available, but the higher core counts are presumably soon to come. There is a slight price premium of around 15-20% for these over the DD2.2 CPUs, but they fix a number of errata including functional hardware watchpoints (no more YOLO mode) and add the new Ultravisor mode for enhanced security (which will be the subject of a future article). In addition, although TDP, clock speed and cache specifications are the same, improved Spectre v2 mitigations in this stepping (specifically count cache flushing with hardware assist) mean possible performance improvements particularly for branch-heavy workloads. Support for this feature should already be in current Linux kernels.
If you have a T2 family system, you can order these today, and the SKUs are reported as in-stock. They are drop-in replacements for all T2s and Blackbirds and because their TDPs are the same can use the same heat sinks and HSFs. Systems shipping now may still have DD2.2 chips in them, though Raptor says you can get a DD2.3 for a slight upcharge.
These price tags are heavy. I'd really like to play around with POWER but waiting for a more affordable product in the future. Something like a POWER Raspberry Pi for 100 bucks or less would be great!
ReplyDeleteIf you want a POWER9 RPi-class system, you might as well ask for a Xeon-based one; there just isn't any at that price point. The CPU alone costs more (both for Power or x86). You'd need to choose one of the embedded Power systems like the NXP parts, which aren't technically OpenPOWER. However, you could probably find an evaluation board for one of those in the several hundred dollar range.
DeleteOtherwise, there's Microwatt. It's still got a long way to go but it works, and it can be synthesised with off-the-shelf components. If you're really that price sensitive, that would be where I would start. Even fairly old FPGA systems can run it.
Yes, what I was thinking of would be more like a stripped down, power consumption reduced, cost reduced, feature reduced version of POWER as we wouldn't need server features and quality in a RasPi style product. Sadly IBM isn't interested in serve home consumers any more but as the ISA has been opened third party products may be fill this gap. The original RasPi products are fine in every aspect but still depend on closed source firmware blobs. This is wehere I'd like to see an alternative like Microwatt or as I would call it: PowerµC...
DeleteIs there a list somewhere of what was fixed in POWER9 DD2.3? Is it just spectre v2, DAWR, and the ultravisor stuff or was some of the other DD2.2 errata also fixed?
ReplyDeleteThere doesn't seem to be anything on Raptor's wiki.
Thanks!