I ran blockbench on a HAMMER partition and on a UFS partition and

    got some rather interesting results.
    I fully expected HAMMER's write performance to be bad compared to UFS,

    because HAMMER is still double-buffering its data.  Indeed, as the

    test began UFS seemed to be outdoing HAMMER.  But as the number of files

    grew and the kernel started to have to recycle vnodes and buffers, UFS's

    performance went completely to hell while HAMMER was able to maintain good

    throughput.  Ths basic blog benchmark creates, reads, and writes around

    20,000 files and goes for a lot of parallelism.
    I don't know why UFS's write performance went to hell.. it pretty much

    died completely after a very promising start.  But even ignoring that

    as some sort of implementation fluke the read performance numbers speak

    for themselves.
    I haven't run bonnie++ yet.  I think UFS still does very well vs HAMMER

    on saturated single-file I/O.
						-Matt
test29# blogbench -d /usr/obj/bench		(HAMMER MOUNT)
Frequency = 10 secs

Scratch dir = [/usr/obj/bench]

Direct I/O: disabled

Spawning 3 writers...

Spawning 1 rewriters...

Spawning 5 commenters...

Spawning 100 readers...

Benchmarking for 30 iterations.

The test will run during 5 minutes.
  Nb blogs   R articles    W articles    R pictures    W pictures    R comments    W comments

        17        90598           894         64890           945         44719          2268

        22        82772           362         63112           348         52860          1002

        32        75915           537         53145           484         49000          1482

        34        86616           188         58819           213         54302           542

        38        85506           179         60253           195         51557           474

        43        73030           441         51141           390         43208          1582

        45        72860           156         51320           226    ...
[ message continues ]

Matthew Dillon wrote:

 >     I ran blockbench on a HAMMER partition and on a UFS partition and

 >     got some rather interesting results.

 >

 >     I fully expected HAMMER's write performance to be bad compared to

UFS,

 >     because HAMMER is still double-buffering its data.  Indeed, as the

 >     test began UFS seemed to be outdoing HAMMER.  But as the number

of files

 >     grew and the kernel started to have to recycle vnodes and

buffers, UFS's

 >     performance went completely to hell while HAMMER was able to

maintain good

 >     throughput.  Ths basic blog benchmark creates, reads, and writes

around

 >     20,000 files and goes for a lot of parallelism.

 >

 >     I don't know why UFS's write performance went to hell.. it pretty

much

 >     died completely after a very promising start.  But even ignoring that

 >     as some sort of implementation fluke the read performance numbers

speak

 >     for themselves.

 >

 >     I haven't run bonnie++ yet.  I think UFS still does very well vs

HAMMER

 >     on saturated single-file I/O.
Would be nice to see some UFS benchmarks of FreeBSD, to make sure it's

not an issue with DragonFly's UFS "implementation". Too sad that I don't

have UFS anymore (only ZFS), so I could do it myself. And then, the

benchmark should be done on one and the same machine. But probably it's

wise to wait a few days for benchmarks :)
Regards,
   Michael