On Mon, Jan 21, 2019 at 1:36 PM Eduardo A. Bustamante López <dual...@gmail.com> wrote: > > On Sun, Jan 20, 2019 at 05:22:12PM -0500, Chet Ramey wrote: > > On 1/20/19 4:54 PM, Chet Ramey wrote: > > > > >> As an aside, I can confirm the findings of a performance difference > > >> between 4.4 and 5.0 when running the script provided earlier in the > > >> discussion. At first glance it seems to be due to the switch from the > > >> old LCG to the current MINSTD RNG, > (...) > > So I ran a quick test. > > > > $ ./bash ./x3 > > iterations: 1000000 > > BASH_VERSION: 5.0.2(4)-maint > > time: 9.684 > > $ ../bash-5.0/bash ./x3 > > iterations: 1000000 > > BASH_VERSION: 5.0.0(1)-release > > time: 9.749 > > $ ../bash-5.0-patched/bash ./x3 > > iterations: 1000000 > > BASH_VERSION: 5.0.2(3)-release > > time: 9.840 > > $ ../bash-4.4-patched/bash ./x3 > > iterations: 1000000 > > BASH_VERSION: 4.4.23(7)-release > > time: 11.365 > > $ ../bash-4.4-patched/bash ./x3 > > iterations: 1000000 > > BASH_VERSION: 4.4.23(7)-release > > time: 11.235 > > jenna.local(1) > > > > Where the script is Eduardo's iterator that just expands $RANDOM > > N times. > > > > The random number generator has been the same since bash-4.0. > > I'm sorry, my tests were wrong. I built bash using the default `./configure' > behavior for the `devel' branch, which I always forget, uses the internal > allocator with debugging enabled, and thus, all of my times were off due to > the > additional malloc overhead. > > I rebuilt it with `../bash/configure --without-bash-malloc', which causes it > to > use the system's allocator, and surely enough, the timings make more sense > now: > > (`build-bash-devel-malloc' is `configure --with-bash-malloc', > `build-bash-devel' is `configure --without-bash-malloc') > > | dualbus@system76-pc:~/src/gnu/build-bash-devel-malloc$ ./bash > ~/test-speed.sh > | iterations: 1000000 > | BASH_VERSION: 5.0.0(1)-maint > | time: 8.765 > | > | dualbus@system76-pc:~/src/gnu/build-bash-devel-malloc$ > ../build-bash-devel/bash ~/test-speed.sh > | iterations: 1000000 > | BASH_VERSION: 5.0.0(1)-maint > | time: 3.431 > | > | dualbus@system76-pc:~/src/gnu/build-bash-devel-malloc$ bash ~/test-speed.sh > | iterations: 1000000 > | BASH_VERSION: 5.0.0(1)-release > | time: 3.435 > | > | dualbus@system76-pc:~/src/gnu/build-bash-4.4$ ./bash ~/test-speed.sh > | iterations: 1000000 > | BASH_VERSION: 4.4.0(1)-release > | time: 3.443
Hi, Perfect timing - I was just about to reply to Chet's earlier message with the following finding: *snip* On Mon, Jan 21, 2019 at 11:22 AM Chet Ramey <chet.ra...@case.edu> wrote: > > On 1/20/19 4:54 PM, Chet Ramey wrote: > > So I ran a quick test. > > [results removed for brevity] That's interesting. For comparison here's what I'm seeing: ▓▒░$ ~/bin/bash5/bash /tmp/randtest # Downloaded and compiled as-is iterations: 1000000 BASH_VERSION: 5.0.0(1)-release time: 7.210 ▓▒░$ ~/bin/bash5lcg/bash /tmp/randtest # With all the RANDOM related code reverted to the 4.4 code iterations: 1000000 BASH_VERSION: 5.0.0(2)-release time: 7.271 ▓▒░$ ~/bin/bash5chacha/bash /tmp/randtest # With Ole's chacha patch iterations: 1000000 BASH_VERSION: 5.0.0(1)-release time: 7.443 ▓▒░$ /bin/bash /tmp/randtest # Distro provided package, wait a minute... iterations: 1000000 BASH_VERSION: 4.4.19(1)-release time: 5.610 I hadn't thought of the pre-compiled package vs source compiled difference until just now. So I figured that while I'd downloaded 4.4's source to double check variables.c, I may as well compile and test it: ▓▒░$ ~/bin/bash44/bash /tmp/randtest iterations: 1000000 BASH_VERSION: 4.4.0(1)-release time: 7.432 So in the best tradition of n=1 science, it looks like the difference may be down to compilation choices? Can anyone else replicate this? */snip* So it looks like problem solved? Rawiri
