Comment 8 for bug 1576763

I've done some performance testing of the patch that removes the frag deflator. The numbers below are in "min-max(avg+/-dev)" formatting and they were gathered with 10 consecutive runs of the following command:

 $ ./mksquashfs nmap_unpack nmap_$i.snap -noappend -comp xz -all-root -no-xattrs -quiet

A) 12 core Xeon E5-2609 v3 with 16GB of ram

Without the frag deflator removal patch:
 real 0.910000-1.010000(0.965+/-0.032)
 user 9.760000-10.060000(9.937+/-0.076)
 sys 0.150000-0.370000(0.235+/-0.073)

With the frag deflator removal patch:
 real 2.930000-3.000000(2.96+/-0.024)
 user 9.460000-9.590000(9.53+/-0.045)
 sys 0.100000-0.140000(0.116+/-0.012)

B) Raspberry Pi 2 (4 core, 1GB of ram)

Without the frag deflator removal patch:
 real 14.960000-15.320000(15.116+/-0.096)
 user 55.100000-55.730000(55.365+/-0.16)
 sys 3.530000-4.170000(3.764+/-0.18)

With the frag deflator removal patch:
 real 20.980000-21.360000(21.107+/-0.13)
 user 51.510000-52.100000(51.694+/-0.19)
 sys 1.410000-1.770000(1.572+/-0.086)

There's a considerable increase in mksquashfs execution time when the frag deflator threads are removed. I would assume that this nmap snap is relatively small compared to other snaps so it might be a factor to keep in mind.