Re: Weird performance problem

[Leandro Lucarella]

David Boyce, el 15 de julio a las 10:34 me escribiste:
> On Wed, Jul 14, 2010 at 2:03 PM, Leandro Lucarella <address@hidden> wrote:
> > Just to clarify, I included the shell in the command invocation to try
> > different shells:
> >
> > all:
> >        bash -c 'program'
> >
> > For example.
> 
> This may not do what you think though - the result *could* be to execute
> 
>     /bin/sh -c "bash -c 'program'"
> 
> The way to change shells is to set "SHELL := /bin/bash" in the Makefile.
> 
> Also, you should consider the "fast path" optimization which removes
> the shell entirely - your test case may be being optimized in this
> way. There's no particular reason to think it's a problem but it is a
> thing you can easily vary and measure. Append a ";" to the command
> line to defeat the optimization and guarantee a shell.
> 
> I would also experiment using the following little Makefile:
> 
> % cat Makefile
> all: ; $(SHELL)
> 
> Now when you type "make" you will have reproduced the exact[*]
> environment within which your test is executed, but interactively.
> This makes it easy to do things like running it from the command line
> while still "within make", comparing the environment from inside and
> out, etc.
> 
> [*] It may not be quite exact because, depending on shell, an
> interactive invocation may drag in different config files from a
> non-interactive one. But I gather you've already ruled out shell
> startup issues.

Thanks! That's a good suggestion for further investigation, I'll let you
know if I find anything interesting.

-- 
Leandro Lucarella (AKA luca)                     http://llucax.com.ar/
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