Bug #85999 Optimize zlib 's fill_window with SIMD instructions
Submitted: 19 Apr 2017 9:14 Modified: 19 Apr 2017 9:55
Reporter: Jun He (OCA) Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: InnoDB storage engine Severity:S5 (Performance)
Version:5.7.17 OS:Any
Assigned to: CPU Architecture:Any

[19 Apr 2017 9:14] Jun He 
Description:
The zlib shipped within MySQL doesn't use advanced instructions for modern CPUs.
This will cause performance drop for InnoDB when compression is used.
The hash table rebase in deflate:fill_window is a typical routine which can be acclerated with SIMD instructions. And hash table rebase can take up to 7% in zlib compression. So it worths integrate SIMD optimized code for this routine. 

How to repeat:
Set compression level to 1.
Run sysbench with InnoDB engine, 10M data records and complex oltp-test-mode.
Check trx with and without SIMD changes.
[19 Apr 2017 9:17] Jun He 
Hash table rebase optimization using Neon

Attachment: fill_window_neon.patch (application/octet-stream, text), 2.52 KiB.
[19 Apr 2017 9:55] MySQL Verification Team 
Hello Jun He,

Thank you for the report and contribution.

Thanks,
Umesh