CVS commit: src/sys/stand/efiboot

["Jared D. McNeill" <jmcneill%netbsd.org@localhost>]

Module Name:    src
Committed By:   jmcneill
Date:           Mon Jun 21 21:18:47 UTC 2021

Modified Files:
        src/sys/stand/efiboot: boot.c efiblock.c efiblock.h

Log Message:
efiboot: Add readahead support.

Reading data through libsa file-systems ends up breaking block I/O
accesses into very small (512-byte or 2048-byte) accesses. This can be
very inefficient, and causes Ampere eMAG w/ BMC image direction to take
_minutes_ to load the install image and kernel. So slow in fact that
the default watchdog timeout will fire before it finishes.

So, when loading big files, optimistically read ahead up to 64KB of data.
Brings the time to boot the install ISO down to around 40 seconds -- still
not ideal but way better than before.


To generate a diff of this commit:
cvs rdiff -u -r1.31 -r1.32 src/sys/stand/efiboot/boot.c
cvs rdiff -u -r1.13 -r1.14 src/sys/stand/efiboot/efiblock.c
cvs rdiff -u -r1.5 -r1.6 src/sys/stand/efiboot/efiblock.h

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