Re: zeroes read back more often than appended

[Pat LaVarre <p.lavarre@ieee.org>]

> No improvement in 2.6.0-test10
> with CONFIG_SMP = CONFIG_PREEMPT = default = on.

Turning SMP off and PREEMPT off again fixes the case of appending
nonzero to a single file, again without improving the case of appending
nonzero to two or more files.

Pat LaVarre

P.S. Relevant tty log include:

$ egrep 'CONFIG_(SMP|PREEMPT)' .config
# CONFIG_SMP is not set
# CONFIG_PREEMPT is not set
$
$ egrep '^CONFIG_DEBUG' .config
CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_SLAB=y
CONFIG_DEBUG_INFO=y
CONFIG_DEBUG_SPINLOCK_SLEEP=y
$
$ date; time fswhd 0 768 mkudffs 0xFF600 0xC8 0x2
Fri Nov 28 10:56:18 MST 2003
Linux 2.6.0-10.udf i686
/home/pat
dd if=/dev/zero of=dd.bin bs=1M seek=0 count=768 2>/dev/null
-rw-rw-r--    1 pat      pat      805306368 Nov 28 10:57 dd.bin
mkudffs 1.0.0b2 for UDF FS 1.0.0-cvs, 2002/02/09
0
hexdump -C whd0.bin | head -3
00000000  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
*
06fbc800  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
hexdump -C whd1.bin | head -3
00000000  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
*
06fbb000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+++ 2.dmesg     2003-11-28 10:59:03.434667328 -0700
+DF-fs DEBUG fs/udf/super.c:1085:udf_load_logicalvol: Partition (0:0) type 1 on volume 1
+UDF-fs DEBUG fs/udf/balloc.c:192:udf_bitmap_free_blocks: bit 12 already set
+UDF-fs DEBUG fs/udf/balloc.c:193:udf_bitmap_free_blocks: byte=70
+UDF-fs DEBUG fs/udf/balloc.c:192:udf_bitmap_free_blocks: bit 13 already set
 
real    2m45.760s
user    0m7.849s
sys     0m7.472s
$
$ date; time fswhd 0 768 mkudffs 0xFF600 0xC8 0x1
Fri Nov 28 11:08:59 MST 2003
Linux 2.6.0-10.udf i686
/home/pat
dd if=/dev/zero of=dd.bin bs=1M seek=0 count=768 2>/dev/null
-rw-rw-r--    1 pat      pat      805306368 Nov 28 11:09 dd.bin
mkudffs 1.0.0b2 for UDF FS 1.0.0-cvs, 2002/02/09
0
hexdump -C whd0.bin | head -3
00000000  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
*
0c783000
 
real    2m12.085s
user    0m3.912s
sys     0m3.393s
$