On Mon, Sep 22, 2025 at 10:59:11AM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Fri, Sep 19, 2025 at 5:50 PM Daniel P. Berrangé <[email protected]>
> wrote:
> 
> > On Fri, Sep 19, 2025 at 05:32:56PM +0400, [email protected]
> > wrote:
> > > From: Marc-André Lureau <[email protected]>
> > >
> > > Running meson on each subproject is quite slow.
> >
> > Why is this faster ?  Does it make meson do parallel downloads
> > if you list then all at once ?
> >
> 
> It doesn't look like it does it in paralllel, yet it is x times faster...
> 
> time sh -c 'for s in keycodemapdb libvfio-user berkeley-softfloat-3
> berkeley-testfloat-3 anyhow-1-rs arbitrary-int-1-rs bilge-0.2-rs
> bilge-impl-0.2-rs either-1-rs foreign-0.3-rs itertools-0.11-rs libc-0.2-rs
> proc-macro2-1-rs proc-macro-error-1-rs proc-macro-error-attr-1-rs
> quote-1-rs syn-2-rs unicode-ident-1-rs; do
>   meson subprojects download $s >/dev/null
> done'
> sh -c   5.27s user 0.33s system 99% cpu 5.613 total
> 
> time sh -c 'meson subprojects download keycodemapdb libvfio-user
> berkeley-softfloat-3 berkeley-testfloat-3 anyhow-1-rs arbitrary-int-1-rs
> bilge-0.2-rs bilge-impl-0.2-rs either-1-rs foreign-0.3-rs itertools-0.11-rs
> libc-0.2-rs proc-macro2-1-rs proc-macro-error-1-rs
> proc-macro-error-attr-1-rs quote-1-rs syn-2-rs unicode-ident-1-rs'
> sh -c   0.32s user 0.01s system 99% cpu 0.339 total

Oh I bet that 0.32secs is the overhead of python importing all modules
that meson uses. Running python 18 times, gives the 5 second overhead.

With regards,
Daniel
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