Anyone else sees a bootstrap failure (Linux-x86)?

Jeff Sturm jsturm@one-point.com
Tue Oct 21 14:10:00 GMT 2003


On Tue, 21 Oct 2003, Andrew Haley wrote:
> Ranjit Mathew writes:
>  > >  > On Solaris 8, I did see an improvement with "-pipe", but it
>  > >  > was always a ~5% improvement.
>  > >
>  > >This is surprising.  You don't say what filesystem you were using.
>  >
>  > It's UFS without journalling, AFAICT.
>  >
>  > But I still don't fully comprehend why "-pipe" cannot be faster -
>  > at some point in time, the OS's filesystem buffers will get full
>  > and will have to be flushed out to the disc, incurring I/O
>  > penalties, during "normal" compilation.
>
> It depends on how the /tmp filesystem behaves.  It can be designed so
> that the creation, use, and subsequent deletion of a temporary file
> never results in any I/O activity at all.

Incidentally, on a normal Solaris installation /tmp is mounted on swapfs,
and incurs no physical I/O at all until physical memory is exhausted.  But
GCC chooses /var/tmp on these hosts, probably so /tmp isn't competing with
with gcc's large memory footprint for limited swap space.

Also disk file operations on Solaris consume relatively high CPU (compared
to Linux or BSD) due to namei operations and the lack of a name-inode
cache.

But all of this is moot.  Of course `-pipe' should work.

Jeff



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