Most efficient log compression method?

bash_log-compression_output

[root@centos ~]# ls -lh
total 5.7G
-rw-r--r--. 1 root root 5.7G Aug 30 06:16 test.log
[root@centos ~]# xz -v -z test.log; gzip -v -9 test.log.xz
test.log (1/1)
  100 %     880.5 KiB / 5,755.4 MiB = 0.000   6.3 MiB/s      15:13             
test.log.xz:	 96.8% -- replaced with test.log.xz.gz
[root@centos ~]# ls -lh
total 28K
-rw-r--r--. 1 root root 28K Aug 30 06:16 test.log.xz.gz
[root@centos ~]# gunzip test.log.xz.gz
[root@centos ~]# ls -lh
total 884K
-rw-r--r--. 1 root root 881K Aug 30 06:16 test.log.xz
[root@centos ~]# xz -v -d test.log.xz
test.log.xz (1/1)
  100 %     880.5 KiB / 5,755.4 MiB = 0.000   167 MiB/s       0:34             
[root@centos ~]# ls -lh
total 5.7G
-rw-r--r--. 1 root root 5.7G Aug 30 06:16 test.log
[root@centos ~]#