D.4 FreeBSD

FreeBSD is another popular Squid platform, and my personal favorite. Table D-2 and Figure D-2 summarize the results for FreeBSD. Again, coss exhibits the highest throughput, followed by diskd . The aufs storage scheme doesn't currently run on FreeBSD. These results come from FreeBSD Version 4.8-STABLE (released April 3, 2003). I built a kernel with the following noteworthy options:

 options         MSGMNB=16384 options         MSGMNI=41 options         MSGSEG=2049 options         MSGSSZ=64 options         MSGTQL=512 options         SHMSEG=16 options         SHMMNI=32 options         SHMMAX=2097152 options         SHMALL=4096 options         MAXFILES=8192 options         NMBCLUSTERS=32768 options         VFS_AIO 

Table D-2. FreeBSD benchmarking results

Storage scheme	Filesystem	Mount options	Throughput	Response time	Hit ratio
coss			330.7	1.58	54.5
diskd(1)	UFS	async , noatime , softupdate	129.0	1.58	54.1
diskd(2)	UFS		77.4	1.47	56.2
ufs(1)	UFS	async , noatime , softupdate	38.0	1.49	56.8
ufs(2)	UFS	noatime	31.1	1.54	55.0
ufs(3)	UFS	async	30.2	1.51	55.9
ufs(4)	UFS	softupdate	29.9	1.51	55.7
ufs(5)	UFS		24.4	1.50	56.4

Figure D-2. FreeBSD filesystem benchmarking traces

Enabling the async , noatime , and softupdate ^[3] options boosts the standard ufs performance from 24 to 38 transactions per second. However, using one of the other storage schemes increases the sustainable throughput even more.

^[3] On FreeBSD, softupdates aren't a mount option, but must be set with the tunefs command.

FreeBSD's diskd performance (129/sec) isn't quite as good as on Linux (169/sec), perhaps because the underlying filesystem ( ext2fs ) is better.

Note that the trace for coss is relatively flat. Its performance doesn't change much over time. Furthermore, both FreeBSD and Linux report similar throughput numbers : 326/sec and 331/sec. This leads me to believe that the disk system isn't a bottleneck in these tests. In fact, the test with no disk cache (see Section D.8) achieves essentially the same throughput (332/sec).