Bug#968963: dpkg-dev: architecture.mk is slow
Package: dpkg-dev Version: 1.20.9 Followup-For: Bug #968963 Control: severity 872381 normal Control: tags -1 patch Control: merge -1 872381 This bug duplicates 872381, which carries a patch.
Bug#968963: dpkg-dev: architecture.mk is slow
On Tue, 2020-08-25 at 14:58:15 +0200, Jakub Wilk wrote: > * Guillem Jover , 2020-08-25, 11:26: > > This seems to be an increasing regression in make: > > I don't belive it is. Indeed! Sorry bad testing procedure from my side. > > $ cat a.mk > > include /usr/share/dpkg/architecture.mk This should have been instead something like: include scripts/mk/architecture.mk > > all: > > true > > (sid)$ time make -f a.mk > > real0m0.824s > > user0m0.702s > > sys 0m0.131s > > (buster)$ time make -f a.mk > > real0m0.396s > > user0m0.351s > > sys 0m0.054s > > Hmm, I don't see any significant difference in speed between buster and sid > chroots here. (Though curiously they are about twice as fast as my normal > sid system.) This seems to have been caused by commit f6e152b63f9eb183313807898be0569f5321bdf6. So now I'm a bit conflicted, because that change still make sense. And while the slow down should not really be visible when building with dpkg-buildpackage as the vars would then be pre-set, it defeats the point of the lazy logic there. So I guess I'll move to adding a new --export-make or similar. Thanks, Guillem
Bug#968963: dpkg-dev: architecture.mk is slow
* Guillem Jover , 2020-08-25, 11:26: This seems to be an increasing regression in make: I don't belive it is. $ cat a.mk include /usr/share/dpkg/architecture.mk all: true (sid)$ time make -f a.mk real0m0.824s user0m0.702s sys 0m0.131s (buster)$ time make -f a.mk real0m0.396s user0m0.351s sys 0m0.054s Hmm, I don't see any significant difference in speed between buster and sid chroots here. (Though curiously they are about twice as fast as my normal sid system.) (stretch)$ time make -f a.mk real0m0.007s user0m0.008s sys 0m0.000s Yes, stretch is fast. But if I upgrade dpkg-dev to the current version, it's as slow as buster or sid. -- Jakub Wilk
Bug#968963: dpkg-dev: architecture.mk is slow
Hi! On Tue, 2020-08-25 at 09:53:32 +0200, Jakub Wilk wrote: > * Jakub Wilk , 2020-08-24, 18:41: > > /usr/share/dpkg/architecture.mk is very slow: > > > > $ time printf 'include /usr/share/dpkg/architecture.mk\nall:\n\ttrue\n' | > > make -f - > /dev/null > > > > real0m1.161s > > user0m1.009s > > sys 0m0.127s > > > > strace tells me this is because it spawns dpkg-architecture 33(!) times. > > This is probably fallout after fixing #888964: lazy evaluation of the > variables doesn't quite work when they are exported. This seems to be an increasing regression in make: $ cat a.mk include /usr/share/dpkg/architecture.mk all: true (sid)$ time make -f a.mk real0m0.824s user0m0.702s sys 0m0.131s (buster)$ time make -f a.mk real0m0.396s user0m0.351s sys 0m0.054s (stretch)$ time make -f a.mk real0m0.007s user0m0.008s sys 0m0.000s > You could use something like this to set all variables with only single > dpkg-architecture call: > > $(foreach var,$(shell dpkg-architecture),$(eval export $(var))) > > But it would need a guard to skip the call if all the variables were already > set in environment. Yes or add a new --print-make command or similar, but meh. I think this might ideally need fixing in make? Thanks, Guillem
Bug#968963: dpkg-dev: architecture.mk is slow
* Jakub Wilk , 2020-08-24, 18:41: /usr/share/dpkg/architecture.mk is very slow: $ time printf 'include /usr/share/dpkg/architecture.mk\nall:\n\ttrue\n' | make -f - > /dev/null real0m1.161s user0m1.009s sys 0m0.127s strace tells me this is because it spawns dpkg-architecture 33(!) times. This is probably fallout after fixing #888964: lazy evaluation of the variables doesn't quite work when they are exported. You could use something like this to set all variables with only single dpkg-architecture call: $(foreach var,$(shell dpkg-architecture),$(eval export $(var))) But it would need a guard to skip the call if all the variables were already set in environment. -- Jakub Wilk
Bug#968963: dpkg-dev: architecture.mk is slow
Package: dpkg-dev Version: 1.20.5 /usr/share/dpkg/architecture.mk is very slow: $ time printf 'include /usr/share/dpkg/architecture.mk\nall:\n\ttrue\n' | make -f - > /dev/null real0m1.161s user0m1.009s sys 0m0.127s strace tells me this is because it spawns dpkg-architecture 33(!) times. Please speed this up. -- System Information: Architecture: i386 Versions of packages dpkg-dev depends on: ii perl 5.30.3-4 ii libdpkg-perl 1.20.5 ii tar 1.30+dfsg-7 ii bzip2 1.0.8-4 ii xz-utils 5.2.4-1+b1 ii patch 2.7.6-6 ii make 4.3-4 ii binutils 2.35-2 -- Jakub Wilk
