From: davidsen@ariel.crd.GE.COM (william E Davidsen) Subject: Re: Jumptable Performance (Was: Re: shared libs - can everyone be happy with this?) Date: 18 Aug 1992 14:08:58 GMT
In article <1992Aug18.080437.3944@fys.ruu.nl>, hooft@fys.ruu.nl (Rob Hooft) writes:
| In <NOP.92Aug17135014@theory.Mankato.MSUS.EDU> nop@theory.Mankato.MSUS.EDU (Jay A. Carlson) writes:
|
| >I'm not sure that all this trouble is worth it. Does anyone have any
| >hard data on the performance loss of jump tables?
|
| Well, I think the only way to correctly test thi is to run the BYTE
| bench again. Especially the 'concurrent shell script' part. I didn't
| do this yet, but I had a very strange experience with the jumptables
| yesterday, and it is reproducible (so far).
| I didn't believe this, so I repeated it many times. Is there any one
| who has an explanation for the fact that the '-jump'ed executable is
| 3% faster? Could this be caused by a difference in the crt0.o?
Have you timed this with the time command (I posted one about 2 weeks
ago to tsx and banjo, hope it's up by now on tsx at least)? I have a
thought that the jump may be effecting the ratio of user/sys time (no, I
don't know how) and that would show it. I believe the flops uses the
user CPU to calculate performance, not the total.
That would also show the realtime, which I would expect to go up.
--
bill davidsen, GE Corp. R&D Center; Box 8; Schenectady NY 12345
I admit that when I was in school I wrote COBOL. But I didn't compile.