Upgrade ZFS v15 to ZFS v28 have problem

[Евгений]

Hello

after the transition from 8.2 release to
# uname-a
FreeBSD ftp.local 8.2-STABLE FreeBSD 8.2-STABLE # 0: Mon Aug 22 12:23:13 
UTC 2011

and updating ZFSv15 to ZFSv28 (# CFLAGS + =- DDEBUG = 1 and # 
DEBUG_FLAGS =- r is off) was reduced productivity by 2-3 times. With 
what may be the reason?

to update when copying speed was 700-800MB after update was 200-250MB :(

--
Eugeny.