MS-DOS/v2.0/source/PROFILE.txt
2018-09-21 17:53:34 -07:00

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MS-DOS PROGRAM PROFILER
FOR .EXE .COM FILES
I. PURPOSE
The PROFIL program is designed to produce an execution
profile of MS-DOS 1.25 or 2.00 .EXE or .COM files on
8086/8088 systems which have a programmable interrupting
clock. The method employed is to chop the program up
into a sequence of "buckets" and to increment the
appropriate (based on CS:IP) bucket count when the clock
interrupts. In addition there are counters for hits
in the I/O system and the DOS so some idea of how I/O
or DOS bound a program is. There is also a bucket for
hits above the program area, you might get counts here
if your program relocates itself, or goes haywire.
The PROFIL program is not intended as an end-user
program, but rather as a developement tool. To this
end it is not particularly robust or friendly, but gets
the job done. The OEM must write a PCLOCK routine (see
PCLOCK.ASM) which implements the hardware dependant clock
interrupt. The implementation should be evident from
examining the source code, it is quite simple. There
is a CLOCKON routine which sets up a clock interrupt
to the CLK_INTER routine every DX micro seconds. A
CLOCKOFF routine which un-does CLOCKON. And a LEAVE_INT
routine which is responsible for the actual "IRET" from
the clock interrupt. Also see the PROHIST documentation.
II. USAGE
The profiler is envoked by uttering:
PROFIL fname.ext
where the filename is completly specified, including
extension. You will then be prompted for the number
of paragraphs in one bucket. This number must be > 0,
based on this number the number of buckets is computed
by using the size of the executable file. Next you will
be prompted for the clock interval, and lastly for
parameters to the program. Type the parameters just
as if you were running the program at the command level.
NOTE: If a "bad" number is entered for the bucket size
or clock interval, you will be reprompted.
When the program terminates, normally or by Cntrl-C,
PROFIL will print a termination message (similar to
debug). The output file will be fname.PRF where fname
is the same as the file containing the program being
profiled.
III. OUTPUT FORMAT
The format of the output file is the following C
type structure.
struct profdata {
short clock_grain; /* Clock sample interval in
micro-seconds*/
short bucket_num; /* The total number of buckets */
short bucket_siz; /* Number of paragraphs per bucket */
short prog_low_pa; /* The Paragraph number of the lower
bound on the sample area */
short prog_high_pa; /* The Paragraph number of the upper
bound on the sample area */
short dos_pa; /* The Paragraph number of the I/O DOS
boundry */
/* When the clock interrupts the current segment is computed
from the CS:IP. If this is below dos_pa it is an I/O hit,
if between dos_pa and prog_low_pa it is a DOS hit, if between
prog_low_pa and prog_high_pa the appropriate bucket number
is computed and that bucket count is incremented, if above
prog_high_pa then it is a high hit. */
short hit_io; /* I/O bucket */
short hit_dos; /* DOS bucket */
short hit_high; /* Above program bucket */
};
short buckets[bucket_num];
/* The buckets *****NOTE: You can't declare it this way
(bucket_num is a variable), the size of this area is
determined by the value of bucket_num in the fixed header
*/