Re: make: should -j affect cwd?

[christos%astron.com@localhost (Christos Zoulas)]

In article <DA47279A-C570-451E-A7A6-634C7C112D0E%cs.columbia.edu@localhost>,
Steven Bellovin  <smb%cs.columbia.edu@localhost> wrote:
>
>On Jan 18, 2012, at 12:10 12PM, Christos Zoulas wrote:
>> 
>> One of the problems with the current make is performance. Doing a simple
>> ktrace , then kdump | grep NAMI reveals that each path is stat'ed four times
>> one of them completely redundant, since it was just stat'ed before. There
>> has been a lot of sandbagging in the path resolution code, to fix bugs by
>> adding extra checks without understanding the original source of the problem.
>> 
>> The second main issue is variable evaluation, and the recent abuse of
>> ${VAR:Uconstantstring}. Running a profiled make in libc reveals that 20%
>> of the run is spent in tolower() and ApplyModifiers(). 50% of the run
>> is spent doing stat().
>
>
>Without disputing any of your factual statements, is this really important?
>Make gets a workout when it's being used to build large projects, but in
>such cases I suspect -- but haven't measured! -- that compilation time
>strongly dominates total runtime.

It is important on slower boxes, but you are right: compilation times are
dominant, specially as the version of gcc increases.

christos