Somewhere between kvm-75 and kvm-78, the
mentioned commands has been slowed down
to insane levels. By "insane" I mean to
take about 10 minutes(!) to save/load a
128MB RAM/1GB HDD VM's state. It used
to require several seconds for much larger
VMs...
Here's a typical sequence of system calls
during savevm:
select(12, [11], [], NULL, NULL) = 1 (in [11])
read(11,
"\f\0\0\0\0\0\0\0\374\377\377\3771s\0\0\350\3\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
128) = 128
close(21) = 0
_llseek(12, 1669340278, [1669340278], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340280, [1669340280], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340282, [1669340282], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340284, [1669340284], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340286, [1669340286], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340288, [1669340288], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340290, [1669340290], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340292, [1669340292], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1674259520, [1674259520], SEEK_SET) = 0
write(12,
"\200\0\0\0c\343\260\0\200\0\0\0c\343\300\0\200\0\0\0c\343\320\0\200\0\0\0c\343\340\0\200"...,
64) = 64
dup(12) = 21
futex(0xf7d621a4, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0xf7d621a0, {FUTEX_OP_SET, 0,
FUTEX_OP_CMP_GT, 1}) = 1
futex(0xf7d62120, FUTEX_WAKE_PRIVATE, 1) = 1
select(12, [11], [], NULL, NULL) = 1 (in [11])
read(11,
"\f\0\0\0\0\0\0\0\374\377\377\3771s\0\0\350\3\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
128) = 128
close(21) = 0
_llseek(12, 1669340294, [1669340294], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340296, [1669340296], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340298, [1669340298], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340300, [1669340300], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340302, [1669340302], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340304, [1669340304], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340306, [1669340306], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340308, [1669340308], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1674259584, [1674259584], SEEK_SET) = 0
write(12,
"[EMAIL PROTECTED]"...,
64) = 64
dup(12) = 21
futex(0xf7d621a4, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0xf7d621a0, {FUTEX_OP_SET, 0,
FUTEX_OP_CMP_GT, 1}) = 1
select(12, [11], [], NULL, NULL) = 1 (in [11])
read(11,
"\f\0\0\0\0\0\0\0\374\377\377\3771s\0\0\350\3\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
128) = 128
close(21) = 0
_llseek(12, 1669340310, [1669340310], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340312, [1669340312], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340314, [1669340314], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340316, [1669340316], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340318, [1669340318], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340320, [1669340320], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340322, [1669340322], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340324, [1669340324], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1674259648, [1674259648], SEEK_SET) = 0
write(12,
"\200\0\0\0c\344\260\0\200\0\0\0c\344\300\0\200\0\0\0c\344\320\0\200\0\0\0c\344\340\0\200"...,
64) = 64
dup(12) = 21
futex(0xf7d621a4, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0xf7d621a0, {FUTEX_OP_SET, 0,
FUTEX_OP_CMP_GT, 1}) = 1
futex(0xf7d62120, FUTEX_WAKE_PRIVATE, 1) = 1
select(12, [11], [], NULL, NULL) = 1 (in [11])
read(11,
"\f\0\0\0\0\0\0\0\374\377\377\3771s\0\0\350\3\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
128) = 128
close(21) = 0
_llseek(12, 1669340326, [1669340326], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340328, [1669340328], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340330, [1669340330], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340332, [1669340332], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340334, [1669340334], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340336, [1669340336], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340338, [1669340338], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1669340340, [1669340340], SEEK_SET) = 0
write(12, "\0\1"..., 2) = 2
_llseek(12, 1674259712, [1674259712], SEEK_SET) = 0
write(12,
"[EMAIL PROTECTED]"...,
64) = 64
dup(12) = 21
futex(0xf7d621a4, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0xf7d621a0, {FUTEX_OP_SET, 0,
FUTEX_OP_CMP_GT, 1}) = 1
futex(0xf7d62120, FUTEX_WAKE_PRIVATE, 1) = 1
select(12, [11], [], NULL, NULL^C <unfinished ...>
As you see, it writes 2 bytes, llseeks to THE SAME
position, writes next 2 bytes and so on. This takes
HUGE amount of time, and can be done, in most cases,
in a single write without any seeks.
Is it just me or are savevm/loadvm/delvm really THAT
broken?
And since migration to disk has been removed too,
there's no way currently to save the VM state...
Thanks!
/mjt
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