Re: linux/Makefile: CONFIG_SHELL and SHELL

Clifford Wolf (clifford@clifford.at)
Mon, 31 Aug 1998 22:20:42 +0200 (MEST)


On 31 Aug 1998, Andreas Schwab wrote:

> Clifford Wolf <clifford@clifford.at> writes:
>
> |> At the top of the Makefile we set the variable CONFIG_SHELL which than
> |> should be a bash (if possible). Why don't setting the variable SHELL to
> |> the value of CONFIG_SHELL? If we need bash features we should force to
> |> use bash - or don't use bash features.
>
> Please do the latter. Setting SHELL to a nonstandard value (different
> from /bin/sh) causes *all* commands to be started with '$(SHELL) -c cmd'
> instead of internally by make (which knows about the /bin/sh parsing
> rules). That would kill performance quite a bit.

I don't know much about the internals of GNU make - and I'm sure you are
right in theory - but this are the values I got:

with "SHELL := $(CONFIG_SHELL)":

real 13m32.125s
user 12m20.000s
sys 0m46.000s

without "SHELL := $(CONFIG_SHELL)":

real 13m14.745s
user 12m18.910s
sys 0m45.030s

As you can see: there is no difference. In fact my version was a few secs
faster (but I have no idea why) ...

- clifford

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Clifford Wolf
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