Is anyone thinking about updating to the fastest announced Zen 2 AM4 cpu?

Tom

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A proud member of the OFA (Old Farts Association).

I have plans to upgrade to the 12 core. Haven't decided on whether to upgrade motherboards. Probably will sit on that decision until the support forum traffic on the ASUS Crosshair VIII Formula die down and things get settled out with the expected frequent BIOS updates.

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Seti@Home classic workunits:20,676 CPU time:74,226 hours

A proud member of the OFA (Old Farts Association)

Is anyone thinking about updating to the fastest announced Zen 2 AM4 cpu?

Tom

Not anytime soon (I should get a discrete GPU first), but half the reason I bought a low-end AM4 processor is to be able to upgrade it in the future. It appears that I should be able to upgrade to a 3900 with a B450 motherboard. I'll have to see when the dust eventually settles.

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Seti@home classic: 1,456 results, 1.613 years CPU time

I have no AMD platforms, and dont think i will invest in the new boards just to run it. I like the server stuff better anyway.

Don't see the value in CPU crunching anymore. I'm running it on my Xeons "just because" and i feel like they are going to waste otherwise. but after I swap the 2080s into the 1080ti system, I will probably cut the CPU work and just let them sit mostly idle and save the power use.

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Seti@Home classic workunits: 29,492 CPU time: 134,419 hours

I played around with cutting out the cpu tasks while watching the power consumption on the UPS front panel on my daily driver. Didn't make a whole lot of difference. Not sure what impact overall knocking out cpu tasks on five hosts with 17 gpus running would make in my overall power bill. Which I just paid today for the year. Oooof! That hurt!

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Seti@Home classic workunits:20,676 CPU time:74,226 hours

A proud member of the OFA (Old Farts Association)

I already pulled the 2x 12cores. Together using like 250w. But only doing the work of say a 1060 or less. Just not worth it to me.

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Seti@Home classic workunits: 29,492 CPU time: 134,419 hours

I have no AMD platforms, and dont think i will invest in the new boards just to run it. I like the server stuff better anyway.

Don't see the value in CPU crunching anymore. I'm running it on my Xeons "just because" and i feel like they are going to waste otherwise. but after I swap the 2080s into the 1080ti system, I will probably cut the CPU work and just let them sit mostly idle and save the power use.

On my now #2 system (Intel) I have started running my "other" project fulltime because it is a cpu only project. The 7 gtx 1060's are still doing seti but unless I spend money to upgrade them, the system is pretty much parked at the RAC it will do.

Tom

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A proud member of the OFA (Old Farts Association).

Hi,

This is an issue with seti.

Consider a multiple of scenarios: Sum up 32768 values A) sequentially B) in sequences of length N using middle sums C) pairwise bottom up (recursive) level first.
a) when all are 'small'
b) when all are 'big'
c) when there are a lot more small values than 'big' ones
d) when there are a lot more big ones than 'small' ones
e) when there are first a lot of 'big' ones
f) when there are first a lot of 'small' ones
g) when the sum exceeds the computational representation to make any difference if anything small is added to.

1. Make a matrix of your answers.

Then there is a hunt for the greatest sum of the individual values sampled in "various ways*"

At some point the Sum is used to divide all values that were summed up.

2. What kind of errors you may encounter depending of the input?
3. How would you deal with it?
4. Which kind of an input would you define as 'hard to compute'?
5. Do those kind of input (noisy data) have any scientific value?
6. How about a 'flat' noisy as usual input with small variance?

--

Petri

*Various ways would be a lengthy lesson of how Seti computes what is a pulse.

For those that are curious, I found an interesting PDF in relation to GPU processing on Nvidia GPUs
Precision & Performance:Floating Point and IEEE 754 Compliance for NVIDIA GPUs

Mathematically, (A + B)+ C does equal A + (B + C).
Let rn(x) denote one rounding step on x. Performing these same computations in single precision floating
point arithmetic in round-to-nearest mode according to IEEE 754, we obtain:

            A + B = 21 × 1:1000000000000000000000110000 : : :
        rn(A + B) = 21 × 1:10000000000000000000010
            B + C = 23 × 1:0010000000000000000000100100 : : :
        rn(B + C) = 23 × 1:00100000000000000000001
        A + B + C = 23 × 1:0110000000000000000000101100 : : :
rn(rn(A + B) + C) = 23 × 1:01100000000000000000010
rn(A + rn(B + C)) = 23 × 1:01100000000000000000001

For reference, the exact, mathematical results are computed as well in the table above. Not only are the results computed according to IEEE 754 different from
the exact mathematical results, but also the results corresponding to the sum rn(rn(A + B) + C) and the sum
rn(A + rn(B + C)) are different from each other. In this case, rn(A + rn(B + C)) is closer to the correct mathematical result than rn(rn(A + B) + C).
This example highlights that seemingly identical computations can produce different results even if all basic
operations are computed in compliance with IEEE 754.

Here, the order in which operations are executed affects the accuracy of the result. The results are independent
of the host system. These same results would be obtained using any microprocessor, CPU or GPU, which
supports single precision floating point.

As we have shown in Section 3, the final values computed using IEEE 754 arithmetic can depend on implementation choices
such as whether to use fused multiplyadd or whether additions are organized in series or parallel. These differences affect computation on the CPU
and on the GPU.
One example of the differences can arise from differences between the number of concurrent threads involved in a computation.
On the GPU, a common design pattern is to have all threads in a block coordinate to do a parallel reduction on data within the block,
followed by a serial reduction of the results from each block. Changing the number of threads per block reorganizes the reduction; if the reduction is addition, then
the change rearranges parentheses in the long string of additions.

Computing results in a high precision and then comparing to results computed in a lower precision can be
helpful to see if the lower precision is adequate for a particular application. However, rounding high precision
results to a lower precision is not equivalent to performing the entire computation in lower precision. This can
sometimes be a problem when using x87 and comparing results against the GPU. The results of the CPU may
be computed to an unexpectedly high extended precision for some or all of the operations. The GPU result
will be computed using single or double precision only.

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To overcome Heisenbergs:
"You can't always get what you want / but if you try sometimes you just might find / you get what you need." -- Rolling Stones

Interesting post Petri. I was just reading a post over at MW@H from Tom Donlon, the new scientist running the project about a recent slew of math errors that has cropped up. He made this comment.

Perhaps this is a computer precision issue, which I thought had been resolved before I joined the project, but maybe not. I'll look into this some more.

From AlanB's analysis, the errors are rounding errors because the client is overflowing the parameter string for the task.

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Seti@Home classic workunits:20,676 CPU time:74,226 hours

A proud member of the OFA (Old Farts Association)

Interesting post Petri. I was just reading a post over at MW@H from Tom Donlon, the new scientist running the project about a recent slew of math errors that has cropped up. He made this comment.

Perhaps this is a computer precision issue, which I thought had been resolved before I joined the project, but maybe not. I'll look into this some more.

From AlanB's analysis, the errors are rounding errors because the client is overflowing the parameter string for the task.

Thanks for the name-check, Keith; however, I should point out that I've been trying to say that the problem over at MW@H isn't the parameter string but the handling of [probably] small numbers when the program is getting near boundaries... And I think a consideration of rounding behaviours may be important, as might be the order in which values are processed. I rather thought that was what Petri was hinting at in his post about SETI above...

Cheers - Al.

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Going back to my days of writing real-time controllers it was often the case that near the lower and upper limits of REAL number calculations things would go astray - both very small REAL and very large REAL would cause all sorts of rounding and shift errors. Whenever possible we worked with INTEGER and tried to avoid DIVIDE operations. Somewhere at home I've got a cookbook of workarounds we used to avoid the limits and doing divisions.
Obviously these workarounds could be more code intensive that doing a simple register addition, and some of them won't work on today's CPUs GPUs as they rely on particular processor instruction sets (and even silicon level bugs) to work.
Then along came half-decent FPUs and we thought that would remove such problems. And thought didn't build Rome in a day as we found out :-(

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

SETI doesn't like me anymore. :(

Greetings,

I used to be at the top of page 10 on the Top Participants leader board. Now I don't show up at all. According to my current RAC I should be on the bottom of the 9th page now. I have checked 3 or 4 times now. I'm no longer there on the leader boards. :( I'm an orphan. :(

Have a great day! :)

Siran

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath

SETI doesn't like me anymore. :(

We LIKE YOU FINE. Its just all those aliens who don't.......

Seriously, I think the timed script that runs to update the Leaderboard hickups every once in a while. I have gone missing earlier this year too.

Wait an hour (or more) and check again.

Don't forget to "refresh" the page :)

Tom

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A proud member of the OFA (Old Farts Association).

SETI doesn't like me anymore. :(

We LIKE YOU FINE. Its just all those aliens who don't.......

Seriously, I think the timed script that runs to update the Leaderboard hickups every once in a while. I have gone missing earlier this year too.

Wait an hour (or more) and check again.

Don't forget to "refresh" the page :)

Tom

Hi Tom,

Yeah, I already refreshed it. I'll do it again later.

Figures them dang aliens would stick their fingers in the pie. lol :D

Have a great day! :)

Siran

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath

You are #185.....

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

You are #185.....

Hi Rob,

Yep, I just saw that. SETI loves me again!!! :)

Have a great day! :)

Siran

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath

I think the general consensus of opinion is that the new Mac Pro is somewhat overpriced.

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Grant
Darwin NT

Its FRIDAY, lets celebrate!

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A proud member of the OFA (Old Farts Association).

just found this, may be interesting for people running Ryzen/Threadripper under Linux:

https://www.reddit.com/r/linux/comments/9djs3b/monitoring_the_power_consumption_of_amd_ryzen_and/

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Its FRIDAY, lets celebrate!

Hey Tom,

It's SATURDAY where I live, here in the mid-west. ;)

Have a great day! :)

Siran

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath