qemu-e2k/qapi
Andrei Gudkov 34a68001f1 migration/calc-dirty-rate: millisecond-granularity period
This patch allows to measure dirty page rate for
sub-second intervals of time. An optional argument is
introduced -- calc-time-unit. For example:
{"execute": "calc-dirty-rate", "arguments":
  {"calc-time": 500, "calc-time-unit": "millisecond"} }

Millisecond granularity allows to make predictions whether
migration will succeed or not. To do this, calculate dirty
rate with calc-time set to max allowed downtime (e.g. 300ms),
convert measured rate into volume of dirtied memory,
and divide by network throughput. If the value is lower
than max allowed downtime, then migration will converge.

Measurement results for single thread randomly writing to
a 1/4/24GiB memory region:

+----------------+-----------------------------------------------+
| calc-time      |                dirty rate MiB/s               |
| (milliseconds) +----------------+---------------+--------------+
|                | theoretical    | page-sampling | dirty-bitmap |
|                | (at 3M wr/sec) |               |              |
+----------------+----------------+---------------+--------------+
|                               1GiB                             |
+----------------+----------------+---------------+--------------+
|            100 |           6996 |          7100 |         3192 |
|            200 |           4606 |          4660 |         2655 |
|            300 |           3305 |          3280 |         2371 |
|            400 |           2534 |          2525 |         2154 |
|            500 |           2041 |          2044 |         1871 |
|            750 |           1365 |          1341 |         1358 |
|           1000 |           1024 |          1052 |         1025 |
|           1500 |            683 |           678 |          684 |
|           2000 |            512 |           507 |          513 |
+----------------+----------------+---------------+--------------+
|                               4GiB                             |
+----------------+----------------+---------------+--------------+
|            100 |          10232 |          8880 |         4070 |
|            200 |           8954 |          8049 |         3195 |
|            300 |           7889 |          7193 |         2881 |
|            400 |           6996 |          6530 |         2700 |
|            500 |           6245 |          5772 |         2312 |
|            750 |           4829 |          4586 |         2465 |
|           1000 |           3865 |          3780 |         2178 |
|           1500 |           2694 |          2633 |         2004 |
|           2000 |           2041 |          2031 |         1789 |
+----------------+----------------+---------------+--------------+
|                               24GiB                            |
+----------------+----------------+---------------+--------------+
|            100 |          11495 |          8640 |         5597 |
|            200 |          11226 |          8616 |         3527 |
|            300 |          10965 |          8386 |         2355 |
|            400 |          10713 |          8370 |         2179 |
|            500 |          10469 |          8196 |         2098 |
|            750 |           9890 |          7885 |         2556 |
|           1000 |           9354 |          7506 |         2084 |
|           1500 |           8397 |          6944 |         2075 |
|           2000 |           7574 |          6402 |         2062 |
+----------------+----------------+---------------+--------------+

Theoretical values are computed according to the following formula:
size * (1 - (1-(4096/size))^(time*wps)) / (time * 2^20),
where size is in bytes, time is in seconds, and wps is number of
writes per second.

Signed-off-by: Andrei Gudkov <gudkov.andrei@huawei.com>
Reviewed-by: Hyman Huang <yong.huang@smartx.com>
Message-Id: <d802e6b8053eb60fbec1a784cf86f67d9528e0a8.1693895970.git.gudkov.andrei@huawei.com>
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
2023-10-10 08:03:50 +08:00
..
acpi.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
audio.json audio/pw: Pipewire->PipeWire case fix for user-visible text 2023-07-17 15:22:56 +04:00
authz.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
block-core.json qemu-img: map: report compressed data blocks 2023-09-20 17:46:01 +02:00
block-export.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
block.json qapi: Reformat recent doc comments to conform to current conventions 2023-07-26 14:51:36 +02:00
char.json ui/vc: do not parse VC-specific options in Spice and GTK 2023-09-04 14:57:37 +04:00
common.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
compat.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
control.json docs/interop: Convert qmp-spec.txt to rST 2023-05-22 10:21:01 +02:00
crypto.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
cryptodev.json spelling: information 2023-06-09 23:38:16 +03:00
cxl.json qapi: Reformat recent doc comments to conform to current conventions 2023-07-26 14:51:36 +02:00
dump.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
error.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
introspect.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
job.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
machine-target.json qapi: Reformat recent doc comments to conform to current conventions 2023-07-26 14:51:36 +02:00
machine.json accel/tcg: remove CONFIG_PROFILER 2023-06-26 17:33:00 +02:00
meson.build meson: Replace CONFIG_SOFTMMU -> CONFIG_SYSTEM_ONLY 2023-06-20 10:01:30 +02:00
migration.json migration/calc-dirty-rate: millisecond-granularity period 2023-10-10 08:03:50 +08:00
misc-target.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
misc.json qapi: Correct "eg." to "e.g." in documentation 2023-07-25 17:20:32 +03:00
net.json net: add initial support for AF_XDP network backend 2023-09-18 14:36:13 +08:00
opts-visitor.c cutils: Adjust signature of parse_uint[_full] 2023-06-02 12:27:19 -05:00
pci.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
pragma.json qapi/pragma: Tidy up comments 2022-05-16 07:31:26 +02:00
qapi-clone-visitor.c
qapi-dealloc-visitor.c
qapi-forward-visitor.c
qapi-schema.json docs/interop: Convert qmp-spec.txt to rST 2023-05-22 10:21:01 +02:00
qapi-type-helpers.c
qapi-util.c
qapi-visit-core.c
qdev.json qapi/qdev: Tidy up device_add documentation 2023-07-26 14:51:36 +02:00
qmp-dispatch.c monitor: mark mixed functions that can suspend 2023-04-20 11:17:35 +02:00
qmp-event.c Replace qemu_gettimeofday() with g_get_real_time() 2022-04-06 10:50:37 +02:00
qmp-registry.c
qobject-input-visitor.c include: add qemu/keyval.h 2022-04-21 17:03:51 +04:00
qobject-output-visitor.c
qom.json backends/hostmem-file: Add "rom" property to support VM templating with R/O files 2023-09-19 10:23:21 +02:00
rdma.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
replay.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
rocker.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
run-state.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
sockets.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
stats.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
string-input-visitor.c
string-output-visitor.c
tpm.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
trace-events
trace.h
trace.json qapi: Reformat recent doc comments to conform to current conventions 2023-07-26 14:51:36 +02:00
transaction.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
ui.json qapi: Reformat recent doc comments to conform to current conventions 2023-07-26 14:51:36 +02:00
virtio.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
yank.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00