of a file in chunks that are less then the filesystem block size, if the
data is not already cached the system will perform a read-before-write.
The problem is that it does this on a block-by-block basis, breaking up the
I/Os and making clustering impossible for the writes. Programs such
as INN using cyclic file buffers suffer greatly. This problem is only going
to get worse as we use larger and larger filesystem block sizes.
The solution is to extend the sequential heuristic so UFS[2] can perform
a far larger read and readahead when dealing with this case.
(note: maximum disk write bandwidth is 27MB/sec thru filesystem)
(note: filesystem blocksize in test is 8K (1K frag))
dd if=/dev/zero of=test.dat bs=1k count=2m conv=notrunc
Before: (note half of these are reads)
tty da0 da1 acd0 cpu
tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
0 76 14.21 598 8.30 0.00 0 0.00 0.00 0 0.00 0 0 7 1 92
0 76 14.09 813 11.19 0.00 0 0.00 0.00 0 0.00 0 0 9 5 86
0 76 14.28 821 11.45 0.00 0 0.00 0.00 0 0.00 0 0 8 1 91
After: (note half of these are reads)
tty da0 da1 acd0 cpu
tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
0 76 63.62 434 26.99 0.00 0 0.00 0.00 0 0.00 0 0 18 1 80
0 76 63.58 424 26.30 0.00 0 0.00 0.00 0 0.00 0 0 17 2 82
0 76 63.82 438 27.32 0.00 0 0.00 0.00 0 0.00 1 0 19 2 79
Reviewed by: mckusick
Approved by: re
X-MFC after: immediately (was heavily tested in -stable for 4 months)
* Change atapi-cd ioctls to use the same units.
* Change burncd, cdcontrol to convert CDROM speed to KB/sec before
calling the ioctl. Add a "max" speed option for their command lines.
This change does not break ABI but does change the units passed through
the ioctl so 3rd party software that uses cdrio.h will have to convert
(most likely by multiplying CDROM speed by 177 to get KB/s).
PR: kern/36845
Submitted by: Philipp Mergenthaler <p@i609a.hadiko.de> (CAM ioctls)
Reviewed by: sos, ken
MFC after: 1 month
In the 'found' case for ext2_lookup() the underlying bp's data was
being accessed after the bp had been releaed. A simple move of the
brelse() solves the problem.
The PR reports that this caused panics running the GDB testsuite unless
NO_GEOM is configured.
PR: 44060
Reported by: Mark Kettenis <kettenis@chello.nl>
MFC after: 3 days
changes for "LSILogic"
(2) enabled non-disk support through CAM interface
(3) HA_INQ (a) enabled tagged queuing (b) disable reset during
driver loading (b) renamed BSDi string to LSI
(4) disabled detecting disk devices during SCSI INQUIRY
(5) changed dcdb single element sglist to send one entire buffer chunk
(6) nsgelem not set in sglist
(7) ap_data_transfer_length not set for dcdb
(8) changed "struct thread" to "d_thread_t" for compatibliity { xxx_open,
xxx_close, xxx_ioctl }
(9) miscellaneous compatiblity fixes
(10) bug fix for 0x0409/0x1000 card
(11) added compiling amr_cam.c in sys/conf/files
(12) added compiling amr_cam.c in sys/modules/amr/Makefile
Reviewed by:ps
MFC after:1 week
1 week
is required to use EAs with UFS2, and that UFS2 is recommend for EA use
for a variety of reasons.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
note that UFS2 doesn't require explicit extended attribute configuration,
and is recommends for this and other reasons if you plan to use ACLs.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
be no major change in performance from this change at this time but this
will allow other work to progress: Giant lock removal around VM system
in favor of per-object mutexes, ranged fsyncs, more optimal COMMIT rpc's for
NFS, partial filesystem syncs by the syncer, more optimal object flushing,
etc. Note that the buffer cache is already using a similar splay tree
mechanism.
Note that a good chunk of the old hash table code is still in the tree.
Alan or I will remove it prior to the release if the new code does not
introduce unsolvable bugs, else we can revert more easily.
Submitted by: alc (this is Alan's code)
Approved by: re
Requested by: Most developers
Apologies to: Most developers, with special note to <ken@kdm.org>
Collabroation in the future with: Kenneth D. Merry <ken@kdm.org>
into memory. This brings us in line with the other architectures and
more easily allows us to do machine dependent processing on the ELF
file (such as scanning for unwind information).
