Kirk Wolf wrote:
If you used LRECL=1, then you did have a record boundary of 1, so it
was doing fwrite() with a length of 1.
This is because todsn() always uses QSAM.
As it turns out, even with a rational DCB, the C library is more
expensive than direct QSAM macros.
For this reason, it is likely that a future version of Co:Z will
bypass the C library for QSAM I/O.
Kirk, have you checked out metal C? I can tell you this - in my
experiments the code generated actually results in faster code then my
hand crafted assembler. I'm very impressed by it. The compiler is
pipeline aware and produces very fast code. If you want to drop down to
using QSAM macros I would recommend it for a QSAM I/O library... It does
bind you up to a z/OS 1.9 system though.
I've noticed that stdio is always less efficient then other languages
for QSAM. This seems to be caused by double buffering due to the
semantics of the stdio library functions. It moves data into the user
supplied buffer with fread() but keeps it's own buffer so is doing two
moves. I've reverse engineered most of the FILE fcb control block for
the M4 port and will commit it to sourceforge soon.
On Fri, Oct 10, 2008 at 8:42 AM, John McKown <[EMAIL PROTECTED]> wrote:
On Fri, 10 Oct 2008 21:16:53 +0800, David Crayford <[EMAIL PROTECTED]> wrote:
CELHVnnn is an XPLINK condition handler. For example CELHV003 is the
XPLINK runtime environment. Im not familiar with CELHV002 but it could
be that the SSL hashes are a CPU hog. If you sending a file that's in a
zFS or HFS cached it may not I/O bound...
I got some advice on another forum about this. The output is a "byte stream"
with no record boundries, pe se. In my job, I had
DCB=(RECFM=FB,LRECL=1,BLKSIZE=0). I changed that to
DCB=(RECFM=U,BLKSIZE=27998). The CPU usage on the exact same job went from
45.82 minutes to 1.33 minutes. Curiously, the elapsed time actually went up
somewhat. Probably due to increased usage on the system during the second test.
--
John
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