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Old 2019-05-06, 21:15   #23
ewmayer
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Odroid N2 arrived last week via express mail (they paid for shipping, as part of the Odroid-magazine piece 'thanks') from Hardkernel ... finally got round to setting it up over the weekend. First impressions: the board is ~50% larger in terms of area than the C2, and the whole thing is much heavier, with the entire bottom of the board - the CPU-side - covered by a massive Alu. heat sink. No fan on this model, but I let it sit on my desk and run full-blast overnight, the heatsink gets warm but no signs of throttling in the resulting timings. Setup mostly same as for the C2, except this time an eMMC preflashed with OS image in place of the similar-sized microSD card for the C2.

/proc/cpuinfo shows the 2 'little' a53 cores labeled cpu0-1 and the 4 'big' a73 cores labeled cpu2-5. Mlucas self-tests give these timings per the resulting mlucas.cfg files - I've edited the data columns to remove roundoff error data and trailing 0-radices in favor of an FFT-performance column which in each table uses the 2048K timing as a baseline and lists the timing divided by the ideal n*log(n) scaling for the larger FFT lengths, in the 'perf = ' column:

[0] Running 2-threaded on the a53 cores (I killed the self-test after it finished 4096K, since will only do DCs on the a53:
Code:
  2048  msec/iter =  135.17  radices = 256 16 16 16  perf = 1.000
  2304  msec/iter =  159.05  radices = 288 16 16 16  perf = 1.036
  2560  msec/iter =  180.14  radices = 160 32 16 16  perf = 1.030
  2816  msec/iter =  209.14  radices = 176 32 16 16  perf = 1.080
  3072  msec/iter =  219.58  radices = 192 32 16 16  perf = 1.028
  3328  msec/iter =  240.32  radices = 208 32 16 16  perf = 1.029
  3584  msec/iter =  258.15  radices = 224 32 16 16  perf = 1.017
  3840  msec/iter =  282.10  radices = 240 32 16 16  perf = 1.028
  4096  msec/iter =  303.91  radices = 256 32 16 16  perf = 1.030
[1] Running 4-threaded on the a73 cores:
Code:
  2048  msec/iter =   37.86  radices = 256 16 16 16  perf = 1.000
  2304  msec/iter =   43.92  radices = 288 16 16 16  perf = 1.015
  2560  msec/iter =   48.30  radices = 160 16 16 32  perf = 0.992
  2816  msec/iter =   54.99  radices = 176 16 16 32  perf = 1.014
  3072  msec/iter =   60.80  radices = 192 16 16 32  perf = 1.017
  3328  msec/iter =   66.33  radices = 208 16 16 32  perf = 1.014
  3584  msec/iter =   71.01  radices = 224 16 16 32  perf = 0.998
  3840  msec/iter =   76.88  radices = 240 16 16 32  perf = 1.001
  4096  msec/iter =   82.08  radices = 256 16 16 32  perf = 0.994
  4608  msec/iter =   94.85  radices = 288 16 16 32  perf = 1.006
  5120  msec/iter =  107.73  radices = 320 16 16 32  perf = 1.016
  5632  msec/iter =  130.55  radices = 176 32 32 16  perf = 1.107
  6144  msec/iter =  135.81  radices = 768 16 16 16  perf = 1.045
  6656  msec/iter =  153.60  radices = 208 32 32 16  perf = 1.081
  7168  msec/iter =  164.06  radices = 224 32 32 16  perf = 1.063
  7680  msec/iter =  179.47  radices = 240 32 32 16  perf = 1.077
Notice how the quad a73 *really* likes the larger leading FFT radices (call them r0), especially above 4M FFT. For example, notice the timing jump from 5120K, where r0 = 320 is supported in v18, to 5632K, where the current largest r0 = 176. I already knew about this ARM-core trend from my tests on the older 4xa53 C2 and on the quad ARM-based CPUs of my cellphone cluster, so already implemented support for r0 = 352 in my v19 dev-branch code a couple months back, shortly after releasing v18. I may not in fact need r0 = 384 for 6144K FFT since I already have r0 = 768 there, but I'll probably implement it anyway in a future version (likely v20) because it can't hurt, and might help on a decent subset of CPUs.

Overall on the N2, the 'big' quadcore gets ~4x the throughput of the 'little' dual-core. (Recall that the experimental-only N1 had a lower-throughput 2xa72|4xa53 combo.) Once I'd done the above self-tests I fired up a DC@2816K on the 2xa53 and a first-time test@5120K on the 4xa73. With both jobs running the DC gest 246 ms/iter and the first-time test gets 118 ms/iter, thus ~10% lower throughput than for the individual big|little timings above. The resulting total throughput is ~1.3x that of one of my Galaxy S7 compute-cluster broke-o-phones, so if one only cares about FLOPS/$ (as opposed to using the N2 with all its handy connector ports for more general purposes), the old-phone route is a clear win.

Now, my desk is already cluttered enough, so having done the basic timing tests, I would happily resell my almost-brand-new N2 for slightly under cost to an interested party - here is the inventory and Hardkernel prices:

ODROID-N2 with 2GByte RAM - $63
12V/2A power supply US plug - $5.50
ODROID-N2 Case Clear - $4
8GB eMMC Module N2 Linux - $12.90

Total = $85.40, plus whatever shipping cost Hardkernel charges. How about $75 including free shipping to the US?

Last fiddled with by ewmayer on 2019-05-06 at 23:42
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Old 2019-05-07, 13:48   #24
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Quote:
Originally Posted by ewmayer View Post
Total = $85.40, plus whatever shipping cost Hardkernel charges. How about $75 including free shipping to the US?
What's the lowest cost of shipping to La Palma? (I'm in no hurry.) Do you take PayPal or would I have to put a USD 100 beer voucher in the post to you?

I already have a Raspberry Pi-2 lined up for the role but it would appear that your kit would be more suited as a telescope controller as it has more and faster USB more and faster cpus, ditto memory and 1G ethernet.

Last fiddled with by xilman on 2019-05-07 at 13:52 Reason: Add last sentence
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Old 2019-05-07, 14:43   #25
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Quote:
Originally Posted by xilman View Post
What's the lowest cost of shipping to La Palma? (I'm in no hurry.) Do you take PayPal or would I have to put a USD 100 beer voucher in the post to you?

I already have a Raspberry Pi-2 lined up for the role but it would appear that your kit would be more suited as a telescope controller as it has more and faster USB more and faster cpus, ditto memory and 1G ethernet.
I am interested in getting one of these, maybe using it as a desktop replacement, especially as I can run Debian Stretch. I was looking here https://www.liymo.com/index.php?rout...product_id=849
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Old 2019-05-07, 15:14   #26
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How is it doing in relation to memory bandwidth? I assume it should be ok as it is only the speed of 1 core of a Q6600.
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Old 2019-05-07, 21:03   #27
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Quote:
Originally Posted by xilman View Post
What's the lowest cost of shipping to La Palma? (I'm in no hurry.) Do you take PayPal or would I have to put a USD 100 beer voucher in the post to you?

I already have a Raspberry Pi-2 lined up for the role but it would appear that your kit would be more suited as a telescope controller as it has more and faster USB more and faster cpus, ditto memory and 1G ethernet.
Paul, easiest way to cost/ship this to you is via a "private eBay sale". Here is the idea: I post a simple "N2 for sale" item with a ridiculous asking price (to keep anyoe else from bidding on it, or to make me me a lot of $ should someone do so despite the price), but allowing would-be-buyers to make offers, and I set the min-offer threshold very low. Ebay has a global shipping program which saves me all the customs-forms hassle - I just pack the item and ship to a US hub, they take care of the rest. You view the item from your locale should give you a shipping-cost based on said locale. If it's not egregious - and it shouldn't be for a roughly 8oz small package like this - you offer me some insanely low price for the item, which minimizes the 10% ebay fee gouge on the sale. Any remaining difference between the $75 I cited and the min-offer price we officially agreed on you can paypal me vai the "send money to friends & family" option sans fee. But that requires you to have an ebay account [ebay UK should be fine] - do you? If so, e-mail me, it should take no more than a few minutes to get the item listing done.

Quote:
Originally Posted by henryzz View Post
How is it doing in relation to memory bandwidth? I assume it should be ok as it is only the speed of 1 core of a Q6600.
The flatness of the n*log(n)-normalized timings I posted indicate mem-bandwidth it well matched to the CPU.
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Old 2019-05-07, 21:38   #28
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Quote:
Originally Posted by paulunderwood View Post
I am interested in getting one of these, maybe using it as a desktop replacement, especially as I can run Debian Stretch. I was looking here https://www.liymo.com/index.php?rout...product_id=849
107 Euros - does that include shipping and tax(es)? And how does that price out for you compared to going directly to the hardkernel.com site?
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Old 2019-05-07, 21:54   #29
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Quote:
Originally Posted by ewmayer View Post
107 Euros - does that include shipping and tax(es)? And how does that price out for you compared to going directly to the hardkernel.com site?
It is £94.90 with a case and transformer. Although I have a spare SD card, I would probably want a big eMMC card -- read 128GB -- running faster-than-SD swap file, if I am to use it as a desktop.
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Old 2019-05-07, 22:06   #30
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Just for grins, I created an eBay listing with an ask of $195 and a min-offer setting of $1. I used a Pi3 as my item template (Odroids are scarce on eBay), so ignore all the Pi3-boilerplate in the listing.

I'd be interested in what shipping charges our 2 Pauls see to their respective locales.
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Old 2019-05-07, 22:13   #31
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Quote:
Originally Posted by ewmayer View Post
Just for grins, I created an eBay listing with an ask of $195 and a min-offer setting of $1. I used a Pi3 as my item template (Odroids are scarce on eBay), so ignore all the Pi3-boilerplate in the listing.

I'd be interested in what shipping charges our 2 Pauls see to their respective locales.
That is a 2 gigabyte RAM version of the board? I want 4GB.

"This item will ship to United Kingdom, but the seller has not specified shipping options. Contact the seller
- opens in a new window or tab
and request a shipping method to your location."
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Old 2019-05-07, 22:19   #32
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Quote:
Originally Posted by paulunderwood View Post
That is a 2 gigabyte RAM version of the board? I want 4GB.
I know - I was hoping to get shipping-cost data to UK and Grand Canaria from you and the other Paul, no need to commit to buy the item involved (I hope).

Quote:
"This item will ship to United Kingdom, but the seller has not specified shipping options. Contact the seller
- opens in a new window or tab
and request a shipping method to your location."
What do you see when you open said new window/tab? In creating the listing I was only allowed to enable/disable the Global Shipping option, so it seems the detailed shipping method for same is specified by the buyer, via the menu item you cite.

Last fiddled with by ewmayer on 2019-05-07 at 22:20
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Old 2019-05-07, 22:29   #33
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Quote:
Originally Posted by ewmayer View Post
I know - I was hoping to get shipping-cost data to UK and Grand Canaria from you and the other Paul, no need to commit to buy the item involved (I hope).


What do you see when you open said new window/tab? In creating the listing I was only allowed to enable/disable the Global Shipping option, so it seems the detailed shipping method for same is specified by the buyer, via the menu item you cite.
Login screen. I don't have a ebay account but I know someone who does.

I want a UK pin plug, 4GB RAM, case and 128GB eMMC. Here that is £166. The US-UK exchange puts it at nearly $200, but then there are import duties for stuff from USA to the UK, even handling fees. So it looks like a local buy is not too bad for me and no hassle for you.
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