[RFC 6/6] migration: Deprecated old compression method
Thomas Huth
thuth at redhat.com
Wed Jun 21 07:14:27 UTC 2023
On 12/06/2023 21.33, Juan Quintela wrote:
> Signed-off-by: Juan Quintela <quintela at redhat.com>
> ---
> docs/about/deprecated.rst | 8 ++++
> qapi/migration.json | 92 ++++++++++++++++++++++++---------------
> migration/options.c | 13 ++++++
> 3 files changed, 79 insertions(+), 34 deletions(-)
>
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 173c5ba5cb..fe7f2bbde8 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -460,3 +460,11 @@ block migration (since 8.1)
> Block migration is too inflexible. It needs to migrate all block
> devices or none. Use driver_mirror+NBD instead.
>
> +old compression method (since 8.1)
> +''''''''''''''''''''''''''''''''''
> +
> +Compression method fails too much. Too many races. We are going to
> +remove it if nobody fixes it. For starters, migration-test
> +compression tests are disabled becase they hand randomly. If you need
"because they fail randomly" ?
> +compression, use multifd compression methods.
> +
> diff --git a/qapi/migration.json b/qapi/migration.json
> index a8497de48d..40a8b5d124 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -244,6 +244,7 @@
> #
> # @compression: migration compression statistics, only returned if
> # compression feature is on and status is 'active' or 'completed'
> +# It is obsolete and deprecated. Use multifd compression methods.
> # (Since 3.1)
> #
> # @socket-address: Only used for tcp, to know what the real port is
> @@ -261,7 +262,8 @@
> # Features:
> #
> # @deprecated: @disk migration is deprecated. Use driver_mirror+NBD
> -# instead.
> +# instead. @compression is obsolete use multifd compression
Use a dot or comma after "obsolete".
> +# methods instead.
> #
> # Since: 0.14
> ##
> @@ -279,7 +281,7 @@
> '*blocked-reasons': ['str'],
> '*postcopy-blocktime': 'uint32',
> '*postcopy-vcpu-blocktime': ['uint32'],
> - '*compression': 'CompressionStats',
> + '*compression': { 'type': 'CompressionStats', 'features': ['deprecated'] },
> '*socket-address': ['SocketAddress'] } }
>
> ##
> @@ -432,7 +434,8 @@
> # compress and xbzrle are both on, compress only takes effect in
> # the ram bulk stage, after that, it will be disabled and only
> # xbzrle takes effect, this can help to minimize migration
> -# traffic. The feature is disabled by default. (since 2.4 )
> +# traffic. The feature is disabled by default. Obsolete. Use
> +# multifd compression methods if needed. (since 2.4 )
> #
> # @events: generate events for each migration state change (since 2.4
> # )
> @@ -503,6 +506,7 @@
> # Features:
> #
> # @deprecated: @block migration is deprecated. Use driver_mirror+NBD
> +# instead. @compress is obsolete use multifd compression methods
dito
> # instead.
> #
> # @unstable: Members @x-colo and @x-ignore-shared are experimental.
> @@ -511,7 +515,8 @@
> ##
> { 'enum': 'MigrationCapability',
> 'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
> - 'compress', 'events', 'postcopy-ram',
> + { 'name': 'compress', 'features': [ 'deprecated' ] },
> + 'events', 'postcopy-ram',
> { 'name': 'x-colo', 'features': [ 'unstable' ] },
> 'release-ram',
> { 'name': 'block', 'features': [ 'deprecated' ] },
> @@ -671,22 +676,24 @@
> # migration, the compression level is an integer between 0 and 9,
> # where 0 means no compression, 1 means the best compression
> # speed, and 9 means best compression ratio which will consume
> -# more CPU.
> +# more CPU. Obsolete, see multifd compression if needed.
> #
> # @compress-threads: Set compression thread count to be used in live
> # migration, the compression thread count is an integer between 1
> -# and 255.
> +# and 255. Obsolete, see multifd compression if needed.
> #
> # @compress-wait-thread: Controls behavior when all compression
> # threads are currently busy. If true (default), wait for a free
> # compression thread to become available; otherwise, send the page
> -# uncompressed. (Since 3.1)
> +# uncompressed. Obsolete, see multifd compression if
> +# needed. (Since 3.1)
> #
> # @decompress-threads: Set decompression thread count to be used in
> # live migration, the decompression thread count is an integer
> # between 1 and 255. Usually, decompression is at least 4 times as
> # fast as compression, so set the decompress-threads to the number
> -# about 1/4 of compress-threads is adequate.
> +# about 1/4 of compress-threads is adequate. Obsolete, see multifd
> +# compression if needed.
> #
> # @throttle-trigger-threshold: The ratio of bytes_dirty_period and
> # bytes_xfer_period to trigger throttling. It is expressed as
> @@ -799,7 +806,9 @@
> # Features:
> #
> # @deprecated: Member @block-incremental is obsolete. Use
> -# driver_mirror+NBD instead.
> +# driver_mirror+NBD instead. Compression is obsolete, so members
> +# @compress-level, @compress-threads, @decompress-threads and
> +# @compress-wait-thread should not be used.
> #
> # @unstable: Member @x-checkpoint-delay is experimental.
> #
> @@ -808,8 +817,11 @@
> { 'enum': 'MigrationParameter',
> 'data': ['announce-initial', 'announce-max',
> 'announce-rounds', 'announce-step',
> - 'compress-level', 'compress-threads', 'decompress-threads',
> - 'compress-wait-thread', 'throttle-trigger-threshold',
> + { 'name': 'compress-level', 'features': [ 'deprecated' ] },
> + { 'name': 'compress-threads', 'features': [ 'deprecated' ] },
> + { 'name': 'decompress-threads', 'features': [ 'deprecated' ] },
> + { 'name': 'compress-wait-thread', 'features': [ 'deprecated' ] },
> + 'throttle-trigger-threshold',
> 'cpu-throttle-initial', 'cpu-throttle-increment',
> 'cpu-throttle-tailslow',
> 'tls-creds', 'tls-hostname', 'tls-authz', 'max-bandwidth',
> @@ -837,16 +849,17 @@
> # @announce-step: Increase in delay (in milliseconds) between
> # subsequent packets in the announcement (Since 4.0)
> #
> -# @compress-level: compression level
> +# @compress-level: compression level. Obsolete and deprecated.
> #
> -# @compress-threads: compression thread count
> +# @compress-threads: compression thread count. Obsolete and deprecated.
> #
> # @compress-wait-thread: Controls behavior when all compression
> # threads are currently busy. If true (default), wait for a free
> # compression thread to become available; otherwise, send the page
> -# uncompressed. (Since 3.1)
> +# uncompressed. Obsolete and deprecated. (Since 3.1)
> #
> -# @decompress-threads: decompression thread count
> +# @decompress-threads: decompression thread count. Obsolete and
> +# deprecated.
> #
> # @throttle-trigger-threshold: The ratio of bytes_dirty_period and
> # bytes_xfer_period to trigger throttling. It is expressed as
> @@ -958,7 +971,9 @@
> # Features:
> #
> # @deprecated: Member @block-incremental is obsolete. Use
> -# driver_mirror+NBD instead.
> +# driver_mirror+NBD instead. Compression is obsolete, so members
> +# @compress-level, @compress-threads, @decompress-threads and
> +# @compress-wait-thread should not be used.
> #
> # @unstable: Member @x-checkpoint-delay is experimental.
> #
> @@ -972,10 +987,14 @@
> '*announce-max': 'size',
> '*announce-rounds': 'size',
> '*announce-step': 'size',
> - '*compress-level': 'uint8',
> - '*compress-threads': 'uint8',
> - '*compress-wait-thread': 'bool',
> - '*decompress-threads': 'uint8',
> + '*compress-level': { 'type': 'uint8',
> + 'features': [ 'deprecated' ] },
> + '*compress-threads': { 'type': 'uint8',
> + 'features': [ 'deprecated' ] },
> + '*compress-wait-thread': { 'type': 'bool',
> + 'features': [ 'deprecated' ] },
> + '*decompress-threads': { 'type': 'uint8',
> + 'features': [ 'deprecated' ] },
> '*throttle-trigger-threshold': 'uint8',
> '*cpu-throttle-initial': 'uint8',
> '*cpu-throttle-increment': 'uint8',
> @@ -1008,7 +1027,7 @@
> # Example:
> #
> # -> { "execute": "migrate-set-parameters" ,
> -# "arguments": { "compress-level": 1 } }
> +# "arguments": { "multifd-channels": 5 } }
> # <- { "return": {} }
> ##
> { 'command': 'migrate-set-parameters', 'boxed': true,
> @@ -1031,16 +1050,18 @@
> # @announce-step: Increase in delay (in milliseconds) between
> # subsequent packets in the announcement (Since 4.0)
> #
> -# @compress-level: compression level
> +# @compress-level: compression level. Obsolete and deprecated.
> #
> -# @compress-threads: compression thread count
> +# @compress-threads: compression thread count. Obsolote and
Obsolete
> +# deprecated.
> #
> # @compress-wait-thread: Controls behavior when all compression
> # threads are currently busy. If true (default), wait for a free
> # compression thread to become available; otherwise, send the page
> -# uncompressed. (Since 3.1)
> +# uncompressed. Obsolete and deprecated. (Since 3.1)
> #
> -# @decompress-threads: decompression thread count
> +# @decompress-threads: decompression thread count. Obsolete and
> +# deprecated.
> #
> # @throttle-trigger-threshold: The ratio of bytes_dirty_period and
> # bytes_xfer_period to trigger throttling. It is expressed as
> @@ -1154,7 +1175,9 @@
> # Features:
> #
> # @deprecated: Member @block-incremental is obsolete. Use
> -# driver_mirror+NBD instead.
> +# driver_mirror+NBD instead. Compression is obsolete, so members
> +# @compress-level, @compress-threads, @decompress-threads and
> +# @compress-wait-thread should not be used.
> #
> # @unstable: Member @x-checkpoint-delay is experimental.
> #
> @@ -1165,10 +1188,14 @@
> '*announce-max': 'size',
> '*announce-rounds': 'size',
> '*announce-step': 'size',
> - '*compress-level': 'uint8',
> - '*compress-threads': 'uint8',
> - '*compress-wait-thread': 'bool',
> - '*decompress-threads': 'uint8',
> + '*compress-level': { 'type': 'uint8',
> + 'features': [ 'deprecated' ] },
> + '*compress-threads': { 'type': 'uint8',
> + 'features': [ 'deprecated' ] },
> + '*compress-wait-thread': { 'type': 'bool',
> + 'features': [ 'deprecated' ] },
> + '*decompress-threads': { 'type': 'uint8',
> + 'features': [ 'deprecated' ] },
> '*throttle-trigger-threshold': 'uint8',
> '*cpu-throttle-initial': 'uint8',
> '*cpu-throttle-increment': 'uint8',
> @@ -1182,7 +1209,6 @@
> 'features': [ 'unstable' ] },
> '*block-incremental': { 'type': 'bool',
> 'features': [ 'deprecated' ] },
> - '*block-incremental': 'bool',
That hunk should go into a previous patch, I think.
> '*multifd-channels': 'uint8',
> '*xbzrle-cache-size': 'size',
> '*max-postcopy-bandwidth': 'size',
> @@ -1205,10 +1231,8 @@
> #
> # -> { "execute": "query-migrate-parameters" }
> # <- { "return": {
> -# "decompress-threads": 2,
> +# "multifd-channels": 2,
> # "cpu-throttle-increment": 10,
> -# "compress-threads": 8,
> -# "compress-level": 1,
> # "cpu-throttle-initial": 20,
> # "max-bandwidth": 33554432,
> # "downtime-limit": 300
Thomas
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