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Rasmus Villemoes
d4011ce0a3
bb.utils.copyfile is called in a few places with identical src and dst
in order to create an st_nlinks==1 version of the file. That that even
works relies on an implementation detail of copyfile (namely, that it
creates a temporary file and then does a rename). Moreover, it's a waste
of time if the file already has st_nlinks==1.
So create a helper that optimizes away the copy in the st_nlinks==1
case. Of course, this helper relies on the same implementation detail,
but that's now contained within bb.utils itself.
To test that we do at least sometimes hit the no-copy path, I tested
locally with
if sstat[stat.ST_NLINK] == 1:
+ bb.note("Woohoo, 2*%d bytes I/O avoided" % sstat[stat.ST_SIZE])
return True
(and the obvious places in oe-core patched), and the do_package log files
are indeed filled with woohoo notes.
(Bitbake rev: 7ae93cf40ab91965147055100432961436bce46c)
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
QEMU Emulation Targets ====================== To simplify development, the build system supports building images to work with the QEMU emulator in system emulation mode. Several architectures are currently supported in 32 and 64 bit variants: * ARM (qemuarm + qemuarm64) * x86 (qemux86 + qemux86-64) * PowerPC (qemuppc only) * MIPS (qemumips + qemumips64) Use of the QEMU images is covered in the Yocto Project Reference Manual. The appropriate MACHINE variable value corresponding to the target is given in brackets.