1) Bite the bullet, and allow unaligned accesses without buffer copies
on the i386 platform. According to some tests run by Andrew Gallatin,
the buffer copy performance hit is greater than the unaligned access
performance hit (especially with jumbo frames). We still need to copy
everywhere else.
2) Enable interrupt moderation with a 100us timeout.
Submitted by: Andrew Gallatin <no longer at duke.edu>
MFC after: 1 week
directories. When enabled via "options UFS_DIRHASH", in-core hash
arrays are maintained for large directories. These allow all
directory operations to take place quickly instead of requiring
long linear searches. For now anyway, dirhash is not enabled by
default.
The in-core hash arrays have a memory requirement that is approximately
half the size of the size of the on-disk directory file. A number
of new sysctl variables allow control over which directories get
hashed and over the maximum amount of memory that dirhash will use:
vfs.ufs.dirhash_minsize
The minimum on-disk directory size for which hashing should be
used. The default is 2560 (2.5k).
vfs.ufs.dirhash_maxmem
The system-wide maximum total memory to be used by dirhash data
structures. The default is 2097152 (2MB).
The current amount of memory being used by dirhash is visible
through the read-only sysctl variable vfs.ufs.dirhash_maxmem.
Finally, some extra sanity checks that are enabled by default, but
which may have an impact on performance, can be disabled by setting
vfs.ufs.dirhash_docheck to 0.
Discussed on: -fs, -hackers
- When both SC_PIXEL_MODE and SC_NO_FONT_LOADING are defined,
quietly drop SC_NO_FONT_LOADING, because the pixel(raster)
console requires font.
- When SC_NO_FONT_LOADING is defined, force SC_ALT_MOUSE_IMAGE.
Without font, the arrow-shaped mouse cursor cannot be drawn.
- Fiddle and simplify some internal macros.
MFC after: 2 weeks
date of the announcement)
couple of URL fixes. From: Petri Koistinen <pkoistin@cs.stadia.fi>
(http://www.byte.com/art/9410/sec8/art3.htm is now a dangling link.
any alternative URL?)
