The difference may be down at the noise level - unless you are doing millions of these a second. For example if you had a *load register,address* in a tight loop- the second time may be much (100?) faster because the conversion of virtual address to real page address will already be done, and the data will be in the processor cache and so does not need to be read from RAM, or a different book etc. I found using a stack rather than a malloc in each function gave more benefit than trying to polish the instructions. Colin
On Wed, 22 Mar 2023 at 17:03, René Jansen <[email protected]> wrote: > That's another interesting take; but I have to be sure that it is used > before I declare the winner. > > > On 22 Mar 2023, at 18:00, David Crayford <[email protected]> wrote: > > > > I can't answer you original question but I doubt if DFP is really that > much faster. I would imagine it's implemented in millicode and not silicone > so is a software implementation at heart. I would be surprised if it beats > BigDecimal on a PC but I could be wrong. > > > > On 23/3/23 00:42, René Jansen wrote: > >> Without reading any documentation (sorry!), the issue at hand is this. > I want to show the performance gains of using DFP (Decimal Floating Point) > for the typical financial application, after I noticed at some other client > their bought packages seldom were compiled using the right compiler options > (some could have run in 1966 or so - well I exaggerate, but a Z9 would not > have been a problem). > >> > >> This is for Java applications, and it proves slightly harder than I > thought. I don’t have object modules to disassemble and while I can do > -XX:+UnlockDiagnosticVMOptions -XX:+PrintAssembly on my mac or any Linux > box, IBM’s J9 seems to ignore these altogether. For Linux and the mac there > is a .so (or .dylib) that even disassembles what you’d otherwise are shown > in hex - https://chriswhocodes.com/hsdis/ which is called hsdis but what > I would not upload to other people’s machines lightly without building it > myself. > >> > >> Does anybody know how to ask the J9 (Java 8) on z/OS how to show me > what it does when the JIT decides native code would be best? > >> > >> many thanks in advance, > >> > >> best regards, > >> > >> René Jansen. > >> > >> > >> > >> ---------------------------------------------------------------------- > >> For IBM-MAIN subscribe / signoff / archive access instructions, > >> send email to [email protected] with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
