Issue 4502: FSFS f6 ./. f7 performance

Here the results of my measurements taken over the last
couple of days.

Summary:

null-export of source code from spinning disk, NTFS Linux:
* packed f6 4x as fast as non-packed f6
* packed f7 20x as fast as non-packed f7
* packed f7 4x as fast as than packed f6
* non-packed f6 1.4x as fast as non-packed f7
-> you want f7 and you want packing

null-log -v -g from spinning disk, NTFS Linux:
* packed f7 6x as fast as packed f6
(non-packed not measured; very likely similar factors as above)

null-export of source code from spinning disk, NTFS Windows:
* packed f7 2.5x as fast as packed f6
  (limited by USB2)

Setup details:

Repository: freebsd-base, r264989 (almost worst case
of non-packed latest shard in packed repositories), ~3GB,
dirs deltified.

Server: svnserve 4G (Linux) / 1G (Windows) cache,
-c 0, revprops cached

Disk: USB3 spinning disk, NTFS format. Windows tests
ran over USB2 limiting throughput to about 1/3.
A thunderbolt SSD was used to determine the impact
of I/O latency (Linux only).

All measurements done in a "cold setup" using svn-bench.
null-export produced
          6,199 directories
         58,000 files
    782,836,361 bytes in files
        326,397 properties
      4,877,614 bytes in properties

null-log -v -g produced
        185,096 revisions, 528 merged in 823 merges
        994,976 msg lines, 3,347 in merged revisions
      1,109,675 changes, 115,618 in merged revisions

Detailed results:

null-export, USB3 HDD, fuse NTFS, Linux
F6 packed 616s
F7 packed 176s
F7 nonpacked 3495s
F6 nonpacked 2546s

null-export, same HDD over USB2, NTFS, Windows
F6 packed 834s
F7 packed 342s
(both were throughput limited)

null-export, Thunderbold SSD, fuse NTFS, Linux
F6 packed 24.2s
F7 packed 18.8s
F6 nonpacked 21.3s
F7 nonpacked 34.7s
(non-packed operation is latency limited on HDD)

null-log, USB3 HDD, fuse NTFS, Linux
F6 packed 809.101s
F7 packed 134.636s

null-log, Thunderbold SSD, fuse NTFS, Linux
F6 packed 211.097s
F7 packed 23.436s
(operation is latency limited on HDD)
Received on 2014-06-19 12:02:25 CEST