Subject: CVS commit: syssrc/sys/sys
To: None <>
From: Jaromir Dolecek <>
List: source-changes
Date: 10/28/2001 22:27:56
Module Name:	syssrc
Committed By:	jdolecek
Date:		Sun Oct 28 20:27:56 UTC 2001

Modified Files:
	syssrc/sys/sys: pipe.h

Log Message:
Use hardcoded 8192 for PIPE_MINDIRECT, rather than being dependant
on PAGE_SIZE. The overhead of setting up Page Loan is pretty much constant
irregardless of page size, so it makes more sense to use fixed constant.

According to hbench, the overhead of Page Loan setup is still significantly
bigger than the performance gain for 4096 byte buffers on i386
(PIII/600Mhz). The difference is smaller on 386DX, but Page Loan is
still not faster for this case.

Also, there is some other code out there which expects 4KB writes
to not block even for 'blocking' write, since it works this
way on some other operating systems.
Partially addresses kern/14246 by Andreas Persson.

To generate a diff of this commit:
cvs rdiff -r1.7 -r1.8 syssrc/sys/sys/pipe.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.