PR/53124 CVS commit: src/sys/uvm

["Jaromir Dolecek" <jdolecek%netbsd.org@localhost>]

The following reply was made to PR kern/53124; it has been noted by GNATS.

From: "Jaromir Dolecek" <jdolecek%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/53124 CVS commit: src/sys/uvm
Date: Sat, 19 May 2018 15:13:26 +0000

 Module Name:	src
 Committed By:	jdolecek
 Date:		Sat May 19 15:13:26 UTC 2018
 
 Modified Files:
 	src/sys/uvm: uvm_bio.c
 
 Log Message:
 change code to take advantage of direct map when available, avoiding the need
 to map pages into kernel
 
 this improves performance of UBC-based (read(2)/write(2)) I/O especially
 for cached block I/O - sequential read on my NVMe goes from 1.7 GB/s to 1.9 GB/s
 for non-cached, and from 2.2 GB/s to 5.6 GB/s for cached read
 
 the new code is conditional now and off for now, so that it can be tested further;
 can be turned on by adjusting ubc_direct variable to true
 
 part of fix for PR kern/53124
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.94 -r1.95 src/sys/uvm/uvm_bio.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.