Performance of AIX 1.2

[Bob English]

In article <1990Aug28.012042.21056 at jdyx.UUCP> shawn at jdyx.UUCP (Shawn Hayes) writes:
>The performance is being gauged by running the same benchmarks under OS/2 and
>AIX 1.2 on the same hardware.  Currently we are finding OS/2 to run about
>twice as fast as AIX 1.2.   Part of the problem is that for this test we
>want all writes to be posted to disk immediately so the test uses an open
>call with sync mode for each of the three files accessed.  

I'm not familiar with the details of OS/2, but AIX probably requires two
disk I/O's for every synchronous write to the file.  One of the writes
updates the data, and the other updates the inode to reflect the data
change.  Unless AIX 1.2 logs its inode updates to a separate spindle
than the data, this will cause two synchronous updates to OS/2's one,
and there's very little that can be done about it.

This, by the way, is one of the many reasons that dbms vendors build
their own filesystems and use raw I/O to access them.

--bob--
renglish at hplabs.hp.com	"I don't know how to speak for 90,000 people."