linux-origin
[Top] [All Lists]

Re: kernel compile time

To: tduffy@xxxxxxxxxxxxxxxxxx (Thomas Duffy)
Subject: Re: kernel compile time
From: kanoj@xxxxxxxxxxxxxxxxxxx (Kanoj Sarcar)
Date: Thu, 1 Jun 2000 11:40:28 -0700 (PDT)
Cc: ananth@xxxxxxx (Rajagopal Ananthanarayanan), linux-origin@xxxxxxxxxxx, skunx@xxxxxxxxxxxxxxxxxxxx
In-reply-to: <Pine.LNX.4.21.0006011101530.17846-100000@xxxxxxxxxxxxxxxxxx> from "Thomas Duffy" at Jun 01, 2000 11:11:32 AM
Sender: owner-linux-origin@xxxxxxxxxxx
> 
> Question:  is this using -j4 MAKE="make -j4" so that it will spawn 4
> proccesses for every subdir?  I have found that doing this yeilds about
> 60 compile proccesses on average during the build.
>

make -j4 ARCH=mips vmlinux.

Kanoj

> On Thu, 1 Jun 2000, Rajagopal Ananthanarayanan wrote:
> 
> > Going to -j4, elapsed time went from 808sec -> 254sec (4:14)
> > which is a scaling of ~3.2 times ... if -j4 had had an
> > elapsed time of 202sec (3:22) then it would have been perfect
> > scaling. But add in the fact that -j4 vs. NO-J would introduce
> > additional complexity in the make itself, which now spawns
> > more processes, etc. ... this shows in the increased system time
> > for -j4; of course the extra system time also counts increased
> > lock contention. For this particular workload (primarily user-mode,
> > little-or-no-shared parallelism), -j4 did pretty good.
> > 
> > Finally, -j6 & -j8 may not discover any extra parallelism
> > in the makes ... one gross way to check this is to watch "top"
> > and see how many "cc" processes are running on an average.
> > If it stays at 4, then -j4 is all that'll work.
> 


<Prev in Thread] Current Thread [Next in Thread>