INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - SET SAMPLING RATE
AX = 4502h
BL = sampling rate for PROF.COM (0 < BL <= 13)
(01h = 8192/s, 04h = 1024/s, 08h = 32/s, 0Dh = 1/s)
CX = sampling rate for VPROD.386
Note:   for PROF.COM, this programs the CMOS clock by setting BL+2 as the
low four bits of CMOS register 0Ah.  The interruption rate is
1 SHL (15 - BL) per second.
SeeAlso: AX=4503h

See also: 2F4501

2F4502 - Microsoft Profiler (PROF.COM/VPROD.386) - SET SAMPLING RATE