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Re: [Qemu-devel] [v4 12/13] migration: Add command to set migration para
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [v4 12/13] migration: Add command to set migration parameter |
Date: |
Tue, 03 Feb 2015 16:28:59 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
On 02/02/2015 04:05 AM, Liang Li wrote:
> Add the qmp and hmp commands to tune the parameters used in live
> migration.
>
> Signed-off-by: Liang Li <address@hidden>
> Signed-off-by: Yang Zhang <address@hidden>
> ---
> hmp-commands.hx | 15 ++++++++++
> hmp.c | 35 ++++++++++++++++++++++
> hmp.h | 3 ++
> include/migration/migration.h | 4 +--
> migration/migration.c | 69
> +++++++++++++++++++++++++++++++++++--------
> monitor.c | 18 +++++++++++
> qapi-schema.json | 52 ++++++++++++++++++++++++++++++++
> qmp-commands.hx | 25 ++++++++++++++++
> 8 files changed, 206 insertions(+), 15 deletions(-)
> +++ b/migration/migration.c
> @@ -66,9 +66,12 @@ MigrationState *migrate_get_current(void)
> .bandwidth_limit = MAX_THROTTLE,
> .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
> .mbps = -1,
> - .compress_thread_count = DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
> - .decompress_thread_count = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
> - .compress_level = DEFAULT_MIGRATE_COMPRESS_LEVEL,
> + .parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] =
> + DEFAULT_MIGRATE_COMPRESS_LEVEL,
Looks okay.
> + .parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
> + DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
> + .parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
> + DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
Hmm - do we really need two parameters here? Remember, compress threads
is used only on the source, and decompress threads is used only on the
destination. Having a single parameter, 'threads', which is set to
compression threads on source and decompression threads on destination,
and which need not be equal between the two machines, should still work,
right?
> +++ b/qapi-schema.json
> @@ -541,6 +541,58 @@
> ##
> { 'command': 'query-migrate-capabilities', 'returns':
> ['MigrationCapabilityStatus']}
>
> +# @MigrationParameter
> +#
> +# Migration parameters enumeration
> +#
> +# @compress-level: Set the compression level to be used in live 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.
> +#
> +# @compress-threads: Set compression thread count to be used in live
> migration,
> +# the compression thread count is an integer between 1 and 255.
> +#
> +# @decompress-threads: Set decompression thread count to be used in live
> migration,
> +# the decompression thread count is an integer between 1 and 255.
> +#
Again, I think you could get by with just a single parameter
'compress-threads', and maybe document that the value is typically set
higher on destination than on source.
> +# Since: 2.3
> +##
> +{ 'enum': 'MigrationParameter',
> + 'data': ['compress-level', 'compress-threads', 'decompress-threads'] }
> +##
> +# @MigrationParameterStatus
> +#
> +# Migration parameter information
> +#
> +# @parameter: the parameter of migration
> +#
> +# @data: pointer to the parameter value
> +#
> +# Since: 2.3
> +##
> +{ 'type': 'MigrationParameterBase',
> + 'data': {'parameter': 'MigrationParameter'} }
> +{ 'type': 'MigrationParameterInt',
> + 'data': {'value': 'int'} }
> +{ 'union': 'MigrationParameterStatus',
Is it worth having independent docs for each of these, rather than
cramming all three under one doc text?
> + 'base': 'MigrationParameterBase',
> + 'discriminator': 'parameter',
> + 'data': { 'compress-level': 'MigrationParameterInt',
> + 'compress-threads': 'MigrationParameterInt',
> + 'decompress-threads': 'MigrationParameterInt'} }
> +#
> +# @migrate-set-parameters
> +#
> +# Set the following migration parameters (like compress-level)
> +#
> +# @parameters: json array of parameter modifications to make
> +#
> +# Since: 2.3
> +##
> +{ 'command': 'migrate-set-parameters',
> + 'data': { 'parameters': ['MigrationParameterStatus'] } }
> +##
Interface looks reasonable to me (but I'm biased, as I suggested it).
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- Re: [Qemu-devel] [v4 10/13] migration: Add the core code for decompression, (continued)
- [Qemu-devel] [v4 11/13] migration: Add interface to control compression, Liang Li, 2015/02/02
- [Qemu-devel] [v4 06/13] arch_init: Add and free data struct for decompression, Liang Li, 2015/02/02
- [Qemu-devel] [v4 13/13] migration: Add command to query migration parameter, Liang Li, 2015/02/02
- [Qemu-devel] [v4 02/13] migration: Add the framework of multi-thread compression, Liang Li, 2015/02/02
- [Qemu-devel] [v4 12/13] migration: Add command to set migration parameter, Liang Li, 2015/02/02
- Re: [Qemu-devel] [v4 12/13] migration: Add command to set migration parameter,
Eric Blake <=