zlib-ng: Slowdown due to high SYS time during vips image compression when using LD_PRELOAD to force zlib-ng usage

This is the difference between standard zlib on a Rpi4 running at 2Ghz, and current zlib-ng master:

pi@pfd:/run/user/1000 $ time vips copy out--12.png  x.png

real	0m0.130s
user	0m0.104s
sys	0m0.048s

pi@pfd:/run/user/1000 $ time LD_PRELOAD=/home/pi/zlib-ng/libz.so.1.2.11.zlib-ng vips copy out--12.png  x.png

real	0m0.364s
user	0m0.073s
sys	0m0.306s

This is the test image: test12.zip

About this issue

Original URL
State: open
Created 3 years ago
Comments: 30 (9 by maintainers)

Most upvoted comments

@AndKe minigzip is an application we use extensively to test and benchmark zlib-ng.

We are not able to install, learn and test every application that uses zlib/zlib-ng in order to test/debug them, and most of the time it is irrelevant because a bug in zlib-ng will usually also be triggered by other programs, like minigzip.

Dead2 on May 9, 2021