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Re: Skipping assembler when producing slim LTO files

On Wed, Sep 24, 2014 at 11:47 PM, Ian Lance Taylor wrote:
> On Wed, Sep 24, 2014 at 10:04 AM, Steven Bosscher wrote:
>> Are you using -pipe? AFAIR this still isn't the default, even on
>> GNU/Linux, but it is typically a lot faster than without.
> Is that true even when TMPDIR is on a ram disk?  There's no obvious
> reason that it should be true in a parallel build.  Using -pipe
> effectively constrains communication between the compiler and the
> assembler to work in PIPE_BUF blocks.  Using TMPDIR introduces no such
> constraints, and in a big program a parallel build should obscure the
> fact that the compiler and assembler are serialized for each
> individual compilation unit.

I've done my most recent timings on a machine that has /dev/md3
mounted on /tmp. That's gcc110 on the compile farm. With/without -pipe
made a significant difference.

If TMPDIR is a tmpfs or other kind of ram disk, I suppose the benefits
would be less (to the point of vanishing). Unfortunately I can't test


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