On Tue, Feb 18, 2014 at 5:20 PM, Shmuel Metz (Seymour J.)
shmuel+ibm-m...@patriot.net wrote:
In
of1dbe6dec.23eaa84d-on85257c83.0046f9a1-85257c83.0047a...@us.ibm.com,
on 02/18/2014
at 08:02 AM, Peter Relson rel...@us.ibm.com said:
So it's probably less about optimizing existing code
On 19 Feb 2014 03:48:24 -0800, in bit.listserv.ibm-main you wrote:
On Tue, Feb 18, 2014 at 5:20 PM, Shmuel Metz (Seymour J.)
shmuel+ibm-m...@patriot.net wrote:
In
of1dbe6dec.23eaa84d-on85257c83.0046f9a1-85257c83.0047a...@us.ibm.com,
on 02/18/2014
at 08:02 AM, Peter Relson
I have to ask: Why they big concern over a few instructions?
Optimisation of a few is not worth the effort these days.
In my opinion, it's not concern, it's pride. Surely all of us
programmers like our code to be the best it can be, within reason.
So it's probably less about optimizing
consistently within a second for a 4-hour period
to impact at all.
-
-teD
-
Original Message
From: Peter Relson
Sent: Tuesday, February 18, 2014 08:02
To: IBM-MAIN@LISTSERV.UA.EDU
Reply To: IBM Mainframe Discussion List
Subject: Re: Branch (was: Performance question - adding)
I have to ask: Why they big
Ted MacNeil wrote
| Pride? Maybe.
making it clear rhat he doesn't get it.
There is a very small book, A mathematician's apology, by G. H. Hardy
that I may well have mentioned here before. In it Hardy identifies
three characteristics that all those who do good, sat all memorable
intellectual
On 17 Feb 2014 10:13:44 -0800, in bit.listserv.ibm-main you wrote:
On Mon, Feb 17, 2014 at 12:06 PM, Elardus Engelbrecht
elardus.engelbre...@sita.co.za wrote:
Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions?
Good question. This is why I asked that loop
On Tue, Feb 18, 2014 at 10:12 AM, John Gilmore jwgli...@gmail.com wrote:
Ted MacNeil wrote
| Pride? Maybe.
making it clear rhat he doesn't get it.
There is a very small book, A mathematician's apology, by G. H. Hardy
that I may well have mentioned here before. In it Hardy identifies
On 2/18/2014 8:16 AM, Clark Morris wrote:
If the code generated by the COBOL compiler at your installation
stinks, review the compile options.
IIRC, the COBOL V5 compiler leap frogs over C/C++ and PL/I to now use
the same, ultra-smart, optimizing compiler back-end used by Java. It
should be
Indeed. My favorite (which is, I suspect, where a lot of Big Numbers come
from) is folks who have clearly extrapolated from a peak rate, like We
peaked at 20,000 transactions per minute over Black Friday, so we need to
be able to support 10 billion per year. But if you dig a bit more, you
find out
In
of1dbe6dec.23eaa84d-on85257c83.0046f9a1-85257c83.0047a...@us.ibm.com,
on 02/18/2014
at 08:02 AM, Peter Relson rel...@us.ibm.com said:
So it's probably less about optimizing existing code (unless it's in
a loop) than about understanding what is best for your new code,
when the development
On Mon, 17 Feb 2014 07:49:18 -0500, Peter Relson wrote:
If the branch technique is faster, and depending on how high a
percentage most of the time (as in most of the time CURRENT will be
zero) is, then the branch technique given as the alternative to no-branch
is likely not optimal. Even with
Combining the thoughts engendered from about three replies, I wonder if
avoiding a branch as follows (on a processor which supports the
instructions) would perform better than branching.
LT R0,CURRENT #LOAD CURRENT AND SET CC
SPM R1 #SAVE CC FROM LT
A R0,SUM #ADD SUM TO IT
IPM R1 #RESTORE CC
On 17/02/2014 10:25 PM, Paul Gilmartin wrote:
Then you get to factor in how much readability is worth to you.
Macros are your friend. But does providing readability at the
programming interface level make such a macro unpleasantly
verbose internally?
Unless your desperately need highly
: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf
Of John McKown
Sent: Monday, February 17, 2014 6:37 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Branch (was: Performance question - adding)
Combining the thoughts engendered from about three replies, I wonder if
avoiding
On Mon, 17 Feb 2014 08:02:40 -0800, Charles Mills wrote:
I got to thinking it would be nice to have a store different instruction (or
make store behave this way automatically under the covers) which would
invalidate the cache only if what it were storing were different from what was
in memory
[mailto:IBM-MAIN@LISTSERV.UA.EDU] On
Behalf Of John McKown
Sent: Monday, February 17, 2014 6:37 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Branch (was: Performance question - adding)
Combining the thoughts engendered from about three replies, I wonder if
avoiding a branch as follows (on a processor
Discussion List
Subject: Re: Branch (was: Performance question - adding)
Another possibility which occurs to me, on newer hardware, is to try out
the BPRP instruction. This also addresses Gil's thought about not fetching
the cache line containing SUM unless it is necessary. Remember this assumes
On 2014-02-17, at 10:36, Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions?
Optimisation of a few is not worth the effort
these days.
Hmmm... No single instruction is worth optimizing.
No single instruction among a million is
Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions?
Good question. This is why I asked that loop question earlier today. But I'm
following this fun thread about the cache, fetch/modify by different CPs and
execution prediction. Just curious of course.
Optimisation
On Mon, Feb 17, 2014 at 12:03 PM, Paul Gilmartin paulgboul...@aim.comwrote:
On 2014-02-17, at 10:36, Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions?
Optimisation of a few is not worth the
effort these days.
Hmmm... No
On Mon, Feb 17, 2014 at 12:06 PM, Elardus Engelbrecht
elardus.engelbre...@sita.co.za wrote:
Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions?
Good question. This is why I asked that loop question earlier today. But
I'm following this fun thread about the
Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf
Of John McKown
Sent: Monday, February 17, 2014 10:09 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Branch (was: Performance question - adding)
On Mon, Feb 17, 2014 at 12:03 PM, Paul Gilmartin paulgboul...@aim.comwrote:
On 2014-02-17, at 10
On a 600 MIPS single engine (z/990 class) 1,000,000 instructions is 0.17% of a
CP. These days?
-
-teD
-
Original Message
From: John McKown
Sent: Monday, February 17, 2014 13:15
To: IBM-MAIN@LISTSERV.UA.EDU
Reply To: IBM Mainframe Discussion List
Subject: Re: Branch (was: Performance question
What does the statement
| 1,000,000 instructions is 0.17% of a CP
mean? What are the dimensions of %
John Gilmore, Ashland, MA 01721 - USA
--
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to
On Mon, 17 Feb 2014 14:04:56 -0500, John Gilmore wrote:
What does the statement
| 1,000,000 instructions is 0.17% of a CP
mean? What are the dimensions of %
I don't know, but it would appear to be a gross oversimplification. Ted should
know as well as anyone here that MIPS is meaningless,
engine (z/990 class) 1,000,000 instructions is 0.17% of a
CP. These days?
-
-teD
-
Original Message
From: John McKown
Sent: Monday, February 17, 2014 13:15
To: IBM-MAIN@LISTSERV.UA.EDU
Reply To: IBM Mainframe Discussion List
Subject: Re: Branch (was: Performance question - adding)
On Mon, Feb 17
Benchmarks, features, tuning knobs, performance bonds all factor in to the
mix. The ones that scare me are the 'theoretically we can run some
gazillion transactions on a mainframe'!
In a message dated 2/17/2014 2:18:47 P.M. Central Standard Time,
charl...@mcn.org writes:
I develop
On Mon, Feb 17, 2014 at 11:36 AM, Ted MacNEIL eamacn...@yahoo.ca wrote:
I have to ask: Why they big concern over a few instructions?
Optimisation of a few is not worth the
effort these days.
-
-teD
-
OK, this then causes me to wonder why IBM has bothered
On 17 February 2014 09:37, John McKown john.archie.mck...@gmail.com wrote:
LT R0,CURRENT #LOAD CURRENT AND SET CC
SPM R1 #SAVE CC FROM LT
A R0,SUM #ADD SUM TO IT
IPM R1 #RESTORE CC FROM LT
STOC R0,SUM,NZ #STORE SUM ONLY IF CC OF LT WAS NZ
Basically this loads CURRENT into R0, setting the
On 2014-02-17, at 10:36, Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions?
Optimisation of a few is not worth the effort
these days.
LOL. If Binyamin's question wasn't worth asking, then IBM would never
have recently introduced
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