Synchronous I/O (non-deferred writes) available

Michael "Ford" Ditto ditto at cbmvax.UUCP
Sat Feb 25 11:54:17 AEST 1989


In article <1417 at mtunb.ATT.COM> jcm at mtunb.UUCP (was-John McMillan) writes:
>    	for (l=0;l<1000;l++) {lseek(fid,0,0); write(fid, b, 4096);}
>    Using O_SYNC:	Real=118.6s User=.05s Sys=8.7s (6386/135MB)
>    			Real=100.8s User=.03s Sys=1.0s (3B1/67MB)
>    Otherwise:		Real=  2.5s User=.04s Sys=2.4s (6386/135MB)
>    			Real=  1.0s User=.01s Sys= .2s (3B1/67MB)

The SYNC vs. non-SYNC ratio seems about right, but I'm a bit surprised
at the 6386 vs. 3B1 ratio.  Is the 3B1 really faster?  Did the 6386
have a really slow disk?  Even so, that wouldn't explain the CPU time.

				Just wondering.
-- 
					-=] Ford [=-

"The number of Unix installations	(In Real Life:  Mike Ditto)
has grown to 10, with more expected."	ford at kenobi.cts.com
- The Unix Programmer's Manual,		...!sdcsvax!crash!kenobi!ford
  2nd Edition, June, 1972.		ditto at cbmvax.commodore.com



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