Re: [PATCH 04/14] init: deps: order network interfaces by link order

From: Alexander Holler
Date: Sun Oct 18 2015 - 06:12:50 EST


Am 18.10.2015 um 07:59 schrieb Greg Kroah-Hartman:
On Sun, Oct 18, 2015 at 07:20:34AM +0200, Alexander Holler wrote:
Am 18.10.2015 um 07:14 schrieb Greg Kroah-Hartman:
On Sun, Oct 18, 2015 at 06:59:22AM +0200, Alexander Holler wrote:
Am 17.10.2015 um 21:36 schrieb Greg Kroah-Hartman:

Again, parallelizing does not solve anything, and causes more problems
_and_ makes things take longer. Try it, we have done it in the past and
proven this, it's pretty easy to test :)

Just because I'm curious, may I ask how I would test that in the easy way
you have in mind? I've just posted the results of my tests (the patch
series) but I wonder what you do have in mind.

Use the tool, scripts/bootgraph.pl to create a boot graph of your boot
sequence. That should show you the drivers, or other areas, that are
causing your boot to be "slow".

So I've misunderstood you. I've read your paragraph as that it's easy to
test parallelizing.

Ah, ok, if you want to parallelize everything, add some logic in the
driver core where the probe() callback is made to spin that off into a
new thread for every call, and when it's done, clean up the thread.
That's what I did many years ago to try this all out, if you dig in the
lkml archives there's probably a patch somewhere that you can base the
work off of to test it yourself.

Hmm, I don't think I will do that because that means to setup a new thread for every call. And it doesn't need much imagination (or experience) that this introduces quite some overhead.

But maybe it makes sense to try out what I'm doing in my patches, starting multiple threads once and then just giving them some work. Will keep that in mind, also I don't think I will post any patch in the next few years. ;)

Regards,

Alexander Holler
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