The block cache implementation in loader has proven to be almost useless, and in worst case even slowing down the disk reads due to insufficient cache size and extra memory copy.
Also the current cache implementation does not cache reads from CDs, or work with zfs built on top of multiple disks.
Instead of an LRU, this code uses a simple hash (O(1) read from cache), and instead of a single global cache, a separate cache per block device.
The cache also implements limited read-ahead to increase performance.
To simplify read ahead management, the read ahead will not wrap over bcache end, so in worst case, single block physical read will be performed to fill the last block in bcache.
Booting from a virtual CD over IPMI:
0ms latency, before: 27 second, after: 7 seconds
60ms latency, before: over 12 minutes, after: under 5 minutes.
Submitted by: Toomas Soome <tsoome@me.com>
Reviewed by: delphij (previous version), emaste (previous version)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D4713
magic number to use V86_CY() instead. These should have been fixed as
part of the cleanup in r226746 but were missed.
The md5 sums of the object files were unchanged, so there should be no
functional change.
PR: 205424
Submitted by: Alexander Kuleshov <kuleshovmail@gmail.com>
MFC after: 1 week
__attribute__((format(...))), and the -fformat-extensions flag was
removed, introduce a new macro in bsd.sys.mk to choose the right variant
of compile flag for the used compiler, and use it.
Also add something similar to kern.mk, since including bsd.sys.mk from
that file will anger Warner. :-)
Note that bsd.sys.mk does not support the MK_FORMAT_EXTENSIONS knob used
in kern.mk, since that knob is only available in kern.opts.mk, not in
src.opts.mk. We might want to add it later, to more easily support
external compilers for building world (in particular, sys/boot).
being defined in <sys/diskmbr.h>. Instead give the symbols here a
"PC98_" prefix. This way, both <sys/diskmbr.h> and <sys/diskpc98.h>
can be included in the same C source file.
The renaming is trivial. The only gotcha is that DOSBBSECTOR is
also redefined from 0 to 1. This because DOSBBSECTOR was always
used in conjunction with an addition of 1. The PC98_BBSECTOR symbol
is defined as 1 and the expression is simplified.
Note: it is not believed that ports are seriously impacted; or at
all for that matter.
Approved by: nyan@
i386 comconsole: don't loop forever if hardware doesn't respond
- clear capability flags when hw timeouts
- retire comc_started status variable and directly use c_flags to see
if comconsole is selected for use
Rework the read/write support in the bios disk driver some to cut down
on duplicated code.
- All of the bounce buffer and retry logic duplicated in bd_read() and
bd_write() are merged into a single bd_io() routine that takes an
extra direction argument. bd_read() and bd_write() are now simple
wrappers around bd_io().
macros to treat the 'slice' field as a real part of the bootdev instead
of as hack that spans two other fields (adaptor (sic) and controller)
that are not used in any modern FreeBSD boot code.
MFC after: 1 week
device (kind) specific unit field to the common field. This change
allows a future version of libefi to work without requiring anything
more than what is defined in struct devdesc and as such makes it
possible to compile said version of libefi for different platforms
without requiring that those platforms have identical derivatives
of struct devdesc.
