Support for 3rd party zlib libraries

Richard Stanway r1ch+nginx at
Tue Jul 29 20:46:03 UTC 2014

I recently came across a modified version of zlib with code contributed by
Intel [1] that makes use of modern CPU instructions to increase
performance. In testing, the performance gains seemed substantial, however
when I tried to use this version with nginx, the following alert types
appeared in the error_log on gzip requests:

2014/07/30 05:20:29 [alert] 22285#0: *739837 gzip filter failed to use
preallocated memory: 65536 of 65520 while sending to client
2014/07/30 05:40:42 [alert] 29462#0: *230460 gzip filter failed to use
preallocated memory: 1040 of 4112

It appears nginx is pre-allocating a buffer based on the original zlib
memory usage patterns, however the Intel optimized version has slightly
higher memory requirements due to padding for SSE functions etc.

Is there a chance this version could be supported by nginx, or a
configuration option made available to control the allocation size?


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