Thanks Thorsten. I haven't dug into the source yet but my guess would be that mksh is performing numerous (re)allocations to make space for appended data, rather than using a more optimistic (but space consuming) method, e.g. growing the target buffer size to double its current requirement.
-- You received this bug notification because you are a member of mksh Mailing List, which is subscribed to mksh. Matching subscriptions: mkshlist-to-mksh-bugmail https://bugs.launchpad.net/bugs/1855167 Title: Comparatively poor += performance Status in mksh: Confirmed Bug description: Heavy use of += notably impacts script performance. Consider the following micro-benchmark (pattered after real script content): i=0 s= while ((i < 30000)); do ((++i)) s+=$i done which creates 138,894 character long string. On my system (macOS 10.14.6, 3.5 GHz i7), this takes ~8 seconds in mksh, compared with ksh's ~0.1s and bash 5's ~0.3s. Here're `real' timing figures from my most recent run (these figures are quite stable): - mksh r57: 0m8.17s - ksh 93u+ 2012-08-01: 0m0.10s - bash 5.0.11(1)-release: 0m0.30s It's no surprise that ksh93 is much faster, given its heavy optimisation. Striking, though, is the poor performance of mksh relative to the latest bash. To manage notifications about this bug go to: https://bugs.launchpad.net/mksh/+bug/1855167/+subscriptions
