* Re: [gentoo-user] Puzzled with duration of chromium emerge under profile 17.0
@ 2017-12-06 20:13 99% ` Alan McKinnon
0 siblings, 0 replies; 1+ results
From: Alan McKinnon @ 2017-12-06 20:13 UTC (permalink / raw
To: gentoo-user
On 06/12/2017 21:10, Mick wrote:
> I discovered that building Chromium with gcc-6.4.0 is taking an inordinately
> longer time on a laptop with 1st gen i7 and 4G of RAM, e.g.:
>
> Wed Sep 27 17:36:53 2017 >>> www-client/chromium-61.0.3163.100
> merge time: 6 hours, 40 minutes and 50 seconds.
>
> Thu Nov 9 17:44:58 2017 >>> www-client/chromium-62.0.3202.89
> merge time: 8 hours, 12 minutes and 30 seconds.
>
> -->switch to gcc-6.4.0
>
> Mon Dec 4 11:39:36 2017 >>> www-client/chromium-62.0.3202.89
> merge time: 20 hours, 2 minutes and 4 seconds.
>
> Wed Dec 6 18:41:13 2017 >>> www-client/chromium-62.0.3202.94
> merge time: 22 hours, 47 minutes and 35 seconds.
>
>
> but not so on another older and lesser Intel(R) Core(TM)2 Duo CPU P7550 @
> 2.26GHz, also with 4G RAM:
>
> Wed Sep 27 22:25:32 2017 >>> www-client/chromium-61.0.3163.100
> merge time: 11 hours, 46 minutes and 18 seconds.
>
> Thu Nov 9 22:09:59 2017 >>> www-client/chromium-62.0.3202.89
> merge time: 13 hours, 16 minutes and 41 seconds.
>
> -->switch to gcc-6.4.0
>
> Sat Dec 2 21:00:59 2017 >>> www-client/chromium-62.0.3202.89
> merge time: 15 hours, 35 minutes and 50 seconds.
>
> Mon Dec 4 03:44:12 2017 >>> www-client/chromium-62.0.3202.94
> merge time: 15 hours, 40 minutes and 18 seconds.
>
>
> Any idea why this is happening? I attach emerge info of the i7 in case you
> can spot something which may be causing this exponential increase in emerge
> times. BTW, on the i7 I had to increase swap because the 4,200,960 KiB swap
> partition was not enough to complete the compilation of version 62.0.3202.89,
> even after I shut down all applications and exited X. O_O
>
Pure gut feel and intuition and nothing else leads me to look in two places:
You use -march=native on the i7 so I assume the same on the Core2? Those
are rather different processors, and google is fond of optimizing deeply
for specific cases (common to all browsers I think). You'd have to ask a
chromium hacker but I'd say the odds are good there are serious
optimizations for i7 that stress your compiler out muchly.
Add to that your i7 is RAM-constrained so you compensate with swap,
which is easily 50,000 times slower with sucky latency. When you use a
disk as RAM, performance tanks. Well, usually it causes a cascade effect
and stuff blows up, but if it completes it will have done so slowly.
If you at all can, shove lots more RAM in that i7. These days RAM is
cheap and it's always by first performance tweak, then SSD.
--
Alan McKinnon
alan.mckinnon@gmail.com
^ permalink raw reply [relevance 99%]
Results 1-1 of 1 | reverse | options above
-- pct% links below jump to the message on this page, permalinks otherwise --
2017-12-06 19:10 [gentoo-user] Puzzled with duration of chromium emerge under profile 17.0 Mick
2017-12-06 20:13 99% ` Alan McKinnon
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox