Atom N270

mrbassie · l33t Joined: 31 May 2013 Posts: 772 Location: over here

lspci shows two cores although apparently this chip only has one with hyperthreading(?)

So am I correct that it should be -j2 and not -j3 under MAKEOPTS? Would it make any real difference either way?

Still a newb to this forum so sorry If I should have bumped an old thread instead of starting this one.

eccerr0r · Posted: Sat Aug 10, 2013 4:46 pm Post subject:

Try it both ways, depends on the workload which is better. I just use -j2 though, it also depends on how much RAM you have. I use -j8 on my i7 despite it only having 4 physical cores plus dual threading, some people say 9 is the best but it's very dependent on load, who is to say that 10 may be optimal to make sure there is no idle time?
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mrbassie · l33t Joined: 31 May 2013 Posts: 772 Location: over here

only 2gigs ram.

guess 'll just change it and see if there's a noticable difference.

thanks for the input

EDIT: -j3 is the way to go, with -j2 compiling was a lot slower.

marmoras · n00b Joined: 12 May 2012 Posts: 14

I use a -j3 on a compaq mini (buffed up with 2gb run), haven't noticed a problem.

eccerr0r · Posted: Mon Aug 26, 2013 9:11 pm Post subject:

It's amazing how much hyperthreading actually helps it seems?

How much of a difference did you see, what did you try building?

I don't have my eeePC 900A and honestly speaking I never tried -j3 as memory pressure (specifically onchip memory cache) was a big worry. Maybe it's not as much as one as I thought.
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marmoras · n00b Joined: 12 May 2012 Posts: 14

Actually, I have compiled a full desktop (mostly out of curiosity); it took a couple of days. I use bins for libreoffice and firefox. After that it was not that bad with updating periodically, worst case scenario I leave it overnight. Compared to the main rig that has a 2600K, you ll get disheartened to compile anything on it.

eccerr0r · Posted: Mon Aug 26, 2013 10:09 pm Post subject:

Then the question also remains... what is your -j on your i7-2600K :) I suspect 4 is too few, and I don't think I'd try 12.

I didn't try playing with it on my current compute box - I just stuck it at 8 and left it... Not all ebuilds support parallel builds anyway I suppose. And yes the i7 is pretty much blowing away all my other machines, even my Core2 Quad, by a good margin. The SSD probably contributes however...

(My Asus eeePC Atom N270 has a non-default SSD in it, which helps quite a bit during compiling. Can't exactly help against true compute speed but unpacking into ramdisk and writing back to disk is much faster than with a mechanical disk (or even the disk that it came with. That POS 4GB SSD card writes so slow...))
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

marmoras · n00b Joined: 12 May 2012 Posts: 14

On the i7 2600K (hyperthread) I used -j9, 2xphys cores +1, but I haven't given it much thought; nor will I, because it's very fast and it doesn't bother me. About the SSD, it might be a problem in the long term with the writes of the temp files. I haven't owned an ssd so really I don't know but may other people can give you insights.

eccerr0r · Posted: Tue Aug 27, 2013 6:29 pm Post subject:

From my machine (the i7-2700K) the 8GB of RAM I think is the biggest contributor since I build on tmpfs. But when it comes time to updating the disk (also when reading the tarball from disk, as well as dealing with the portage tree) the ssd makes a huge difference.

Despite running Gentoo, I haven't eaten that much life out of either of the two SSDs that I can monitor erase cycles (the 180G in my i7 and a 128G in my i5), I hope the 32G in my eeePC is similar. I expect the 32G to fail first though, just because it's older.

Still somewhat interesting to squeeze every bit out of it that I can. Despite the Atom being quite slow, the eeePC with its SSD keeps up with my p3-class boxes that have slow mechanical hard drives in them...
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

mrbassie · l33t Joined: 31 May 2013 Posts: 772 Location: over here

eccerr0r · Posted: Tue Aug 27, 2013 7:17 pm Post subject:

Hmm. I don't think the -j2 to -j3 change could have caused that much of a jump, something else must have changed... I could expect it to drop if the machine needed to swap with -j3, but an increase in speed? Something strange going on here.
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
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mrbassie · l33t Joined: 31 May 2013 Posts: 772 Location: over here

That is genuinely the only change I made, it was an update I should mention.

depontius · Advocate Joined: 05 May 2004 Posts: 3509

eccerr0r · Posted: Wed Aug 28, 2013 12:11 pm Post subject: