GNU bug report logs - #72688
big lets are deathly slow

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: spacecadet <spacecadet <at> purge.sh>
To: bug-guile <at> gnu.org
Subject: big lets are deathly slow
Date: Sat, 17 Aug 2024 20:47:03 +0000

performance of let seems to be about O(n^2) for n bindings

bash script to reproduce


range="$1"
time guile --no-auto-compile <( printf "(let ("; for i in $(seq 0 $range); do printf "(foo%s 'bar)" $i; done; printf ") '())" )


$ ./let.sh 10000

real    0m1.059s
user    0m1.306s
sys     0m0.064s

$ ./let.sh 20000

real    0m3.901s
user    0m4.197s
sys     0m0.078s

$ ./let.sh 40000

real    0m14.955s
user    0m15.707s
sys     0m0.188s

$ ./let.sh 80000
./let.sh: line 2:  6182 Segmentation fault      guile --no-auto-compile <( printf '(let ('; for i in $(seq 0 $range); do printf '(foo%s '"'"'bar)' $i; done; printf ") '())" )

real    0m58.146s
user    0m59.156s
sys     0m0.326s

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