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Messages - pocock

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196

Thanks for that feedback

This is the Arty A7 board:
https://reference.digilentinc.com/reference/programmable-logic/arty-a7/start

and it has a radio module that can do things like Zigbee:
https://store.digilentinc.com/pmod-rf2-ieee-802-15-rf-transceiver/

That could make it an interesting competitor for devices like the Zigate USB dongles.  Note that Zigate is currently programmed using a proprietary toolchain and the Arty A7 radio module also requires what appears to be a proprietary SDK right now.

It would be interesting to see all of that opened up like the POWER ISA.

197

Search engines return a lot of publicity about Microwatt but I couldn't see any practical examples of hardware and operating systems

Which FPGAs are people aiming for or testing right now?

Is it at the stage where somebody could build something vaguely similar to a Raspberry Pi, even if it lacks some of the ports?

Is it stable enough to run any GNU/Linux or BSD OS right now?


198

Another thing that comes to mind: AMD's Big Navi cards are coming later in 2020.  It may be wise not to buy any large GPUs, Pro or prosumer, if better cards will arrive in less than 6 months.  Key benefits of the Big Navi may be support for AV1 video decoding, which will be standard for Youtube and Netflix in the future, ray tracing and another step change in power consumption, heat dissipation and noise figures.

2) if you're after lower power consumption (pro cards use binned silicon, lower voltages, lower clocks

The RX 5700 vs the RX 5700 XT:
RX 5700 has the lower clocks and lower overall power use, much like the Pro W5700

3) you really need more than 3 displayports 1.4

Yes, this is another point I had noticed.  The W5700 has 5 mini-DisplayPorts and 1 USB C so you can build a six-screen configuration for a trader desktop using just one GPU.  Previously people would use 2 GPUs, 4 slots and a bigger PSU to create those systems.

so yeah, not worth the price premium most of the time.

Given that the specs vary with each new generation of these cards, that threshold is not always clear.  There are projects were I felt completely comfortable specifying the relevant Pro card (whether it was AMD or NVIDIA) but in the case of Raptor users, the criteria change even further.

there are actual two-slot versions of RX5700/5700XT which won't take away slot space on blackbird:

Thanks for highlighting these, that saves a lot of manual searching.

https://www.powercolor.com/product?id=1565953800
https://www.asrock.com/Graphics-Card/AMD/Radeon%20RX%205700%20XT%20Challenger%20D%208G%20OC/

I have the ASRock and it works well (and it's basically inaudible regardless of load). I have a 10G NIC in the second PCIe and it fits fine.

Of course, the reference versions are also 2-slot, but they're also noisy and run hot.

The 10G NIC is full height or half height?

A full height card would fully cover at least one of those intake fans.  Search results don't reveal anything helpful about the wisdom of doing that but for any Blackbird user, they have nowhere else to put the card, unless they have a case that is large enough to use a PCIe 4.0 compatible riser cable to mount the 8x card elsewhere.

199

In terms of the RX 5700 / Pro W5700, one of the most interesting finds is the Tom's Hardware review of the Sapphire Pulse RX 5700 XT.  There is also a long reddit discussion about which card is actually quietest.

The key points:

- the Sapphire has two BIOS chips and a DIP switch to choose one or the other.  One BIOS gives you gamer performance (higher clock rate, uses more power), the other BIOS gives you a conservative performance profile that looks almost identical to the Pro W5700

- the OEM cooling solution is more effective, so the fans run more slowly, more quietly and may last longer

- it is a little bigger than two slots.  On Talos II you definitely lose one slot but on Blackbird, where the slots are separated more, you might still lose the second slot and as there are only two slots on Blackbird, that would be a headache for many people.

In terms of supporting Raptor, I don't think the extra price of the WX 7100 goes into their pockets.  By saving $500 on this card, you are half way to buying another Blackbird board, you could give that money to somebody who does porting work, you could spend it on trips to events where you demo the product and these things would all do more to support Raptor and the OpenPOWER ecosystem.

For me, it is not about price sensitivity, it is about

a) identifying what features I actually need

b) do I need to buy a Pro version to get any of those features?  Or in the case of noise, it appears the OEM version is actually quieter, paying less gives me that feature.

200

The RX 5700 came out last year and it was followed 6 months later by the Pro version, specifically the Radeon Pro W5700.

The W5700 is basically double the price of the RX 5700.  From the perspective of a POWER user, is this worthwhile?

Summarizing some of the key differences in the Pro version:

- AMD is testing the hardware and drivers more thoroughly: but do they test on any POWER9 systems?

- AMD is releasing driver updates for the Pro cards on a regular schedule: do these bug fixes appear in the amdgpu release for Linux users just as quickly?

- the marketing material describes various features, such as the AMD Remote Workstation (use your GPU remotely from a laptop) but is that relevant for a Linux user?  The software they offer is proprietary, so there are a large percentage of people in this space who would not use it anyway and we also have free software alternatives

- the last significant benefit I could see: the overall design is less aggressive, slightly less power consumption and lower clockrates than other cards so even ignoring the questions about drivers, maybe it will last longer and be more stable

- some people justified the purchase of Radeon Pro products when they included ECC RAM but in the W5700, it is not ECC, it is the same as the RX 5700

I've got an open mind about this: for example, an OEM built RX 5700 that has liquid cooling and isn't overclocked may be more relevant to some people than the W5700.  But if AMD is regularly testing amdgpu with W5700 on POWER9 then that alone would make me feel they are investing in this architecture.

201
Applications and Porting / Re: VP9 benchmarks: have they improved?
« on: June 05, 2020, 12:18:35 pm »

This blog post gives some detailed discussion about VPX / VP9 / VP8 as it relates to POWER9 and other platforms.

202
Applications and Porting / VP9 benchmarks: have they improved?
« on: June 05, 2020, 12:12:38 pm »

One of the top search results for VP9 benchmarks is this OpenBenchmarking.org site where POWER9 is the slowest with 9.37 frames per second (less than real time).  Even the Intel i3 achieves 28.38 fps (better than real time).

Has this code been fixed and does anybody know how to get fresh results in that site?  I think it is very unfair to the platform when search engines show something like that if it is no longer valid.

On the other hand, if it is not fixed, has anybody proposed a bounty for working on it?  IBM is asking people to suggest issues that they will fund

203

Linux provides a mechanism to disable individual cores.  This can be useful to reduce peak power consumption or to simulate a smaller environment, for example, if a developer with a Talos II wants to know how their application would perform on a Blackbird with a 4-core CPU, they can turn off all but 4 cores.

echo 0 | sudo tee /sys/devices/system/cpu/cpu1/online

Spoiler: If you put all the cores of one CPU offline with that command then you won't be able to access the RAM and PCI slots connected to that CPU and you might observe strange behaviour.

Is it possible to go one step further and completely power down a CPU socket and maybe the associated RAM banks too, almost as if they were removed from the board?

There is some documentation about Linux kernel hotplug and it suggests x86 only.  Maybe this would be good for another bounty but first it is important to understand whether the Raptor and POWER9 hardware supports this and whether it would lead to energy savings or other benefits.

Problems that would be solved with this:

- reducing heat output from Talos II workstations during summer heatwaves

- extending runtime for a system on UPS batteries

204
For anything like the problem you describe, the best thing to do is to open a bug report and give them a sample input file, output file and command line

It is also important to give them output of these commands:

ffmpeg -v

ffmpeg -buildconf

This particular thread was about performance but obviously correct functionality is even more important than speed.

205
General CPU Discussion / Re: equivalent to a HP Z cooler?
« on: June 05, 2020, 02:06:49 am »

The HP Z cooler is not simply fanless, it is based on 3D vapor chamber phase-change cooling with staggered hex-fin heat exchangers

HP published some research about this technology

206
General OpenPOWER Discussion / Re: Price getting higher and higher
« on: June 04, 2020, 12:50:49 pm »

207

Mozilla's bug tracker lists a range of PPC related issues, including problems with the WebRTC stack and Youtube:
https://bugzilla.mozilla.org/buglist.cgi?quicksearch=ppc

I made a post about the bounties on the gstreamer-devel mailing list, some suggestions about future bounty projects have already appeared:
https://lists.freedesktop.org/archives/gstreamer-devel/2020-June/075144.html

208
Blackbird / Re: power consumption figures?
« on: June 03, 2020, 08:20:16 am »
I feel it might be a good idea to split the tables in both the Talos II and Blackbird pages.  One table would only have wall socket measurements and the other table would have per-component measurements.


209
A bounty recently provided fixes for ffmpeg

Are similar fixes needed for gstreamer or any of its dependencies?

Could lessons from the ffmpeg porting be applied to any other similar multimedia frameworks, for example, gstreamer, the WebRTC media stacks in Firefox and Chrome?

210
Blackbird / Re: power consumption figures?
« on: June 02, 2020, 02:48:26 pm »
On the fourth row, for Blackbird bundle, do those figures include the CPU power usage or it is necessary to add the CPU figure from above?

The paragraph above the table suggests that power was measured at the wall, that implies the bundle figures include the CPU power.

It also seems very odd that the top row, a 4-core CPU running at 2.15GHz is using more power (54W) than the 8-core CPU at 3.8GHz (34W).  Is the figure for a 4-core system based on the complete bundle, motherboard, RAM, etc?

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