migration: increase max-bandwidth to 128 MiB/s (1 Gib/s)

[PATCH] migration: increase max-bandwidth to 128 MiB/s (1 Gib/s)

Posted by Laurent Vivier 3 years, 7 months ago

max-bandwidth is set by default to 32 MiB/s (256 Mib/s)
since 2008 (5bb7910af031c).

Most of the CPUs can dirty memory faster than that now,
and this is clearly a problem with POWER where the page
size is 64 kiB and not 4 KiB.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 migration/migration.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration/migration.c b/migration/migration.c
index 58a5452471f9..1c4174947181 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -57,7 +57,7 @@
 #include "qemu/queue.h"
 #include "multifd.h"
 
-#define MAX_THROTTLE  (32 << 20)      /* Migration transfer speed throttling */
+#define MAX_THROTTLE  (128 << 20)      /* Migration transfer speed throttling */
 
 /* Amount of time to allocate to each "chunk" of bandwidth-throttled
  * data. */
-- 
2.26.2

Re: [PATCH] migration: increase max-bandwidth to 128 MiB/s (1 Gib/s)

Posted by David Gibson 3 years, 7 months ago

On Mon, Sep 21, 2020 at 04:49:57PM +0200, Laurent Vivier wrote:
> max-bandwidth is set by default to 32 MiB/s (256 Mib/s)
> since 2008 (5bb7910af031c).
> 
> Most of the CPUs can dirty memory faster than that now,
> and this is clearly a problem with POWER where the page
> size is 64 kiB and not 4 KiB.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  migration/migration.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 58a5452471f9..1c4174947181 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -57,7 +57,7 @@
>  #include "qemu/queue.h"
>  #include "multifd.h"
>  
> -#define MAX_THROTTLE  (32 << 20)      /* Migration transfer speed throttling */
> +#define MAX_THROTTLE  (128 << 20)      /* Migration transfer speed throttling */
>  
>  /* Amount of time to allocate to each "chunk" of bandwidth-throttled
>   * data. */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: [PATCH] migration: increase max-bandwidth to 128 MiB/s (1 Gib/s)

Posted by Greg Kurz 3 years, 7 months ago

On Mon, 21 Sep 2020 16:49:57 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> max-bandwidth is set by default to 32 MiB/s (256 Mib/s)
> since 2008 (5bb7910af031c).
> 
> Most of the CPUs can dirty memory faster than that now,
> and this is clearly a problem with POWER where the page
> size is 64 kiB and not 4 KiB.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  migration/migration.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 58a5452471f9..1c4174947181 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -57,7 +57,7 @@
>  #include "qemu/queue.h"
>  #include "multifd.h"
>  
> -#define MAX_THROTTLE  (32 << 20)      /* Migration transfer speed throttling */
> +#define MAX_THROTTLE  (128 << 20)      /* Migration transfer speed throttling */
>  
>  /* Amount of time to allocate to each "chunk" of bandwidth-throttled
>   * data. */

Re: [PATCH] migration: increase max-bandwidth to 128 MiB/s (1 Gib/s)

Posted by Dr. David Alan Gilbert 3 years, 7 months ago

* Laurent Vivier (lvivier@redhat.com) wrote:
> max-bandwidth is set by default to 32 MiB/s (256 Mib/s)
> since 2008 (5bb7910af031c).
> 
> Most of the CPUs can dirty memory faster than that now,
> and this is clearly a problem with POWER where the page
> size is 64 kiB and not 4 KiB.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Queued

> ---
>  migration/migration.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 58a5452471f9..1c4174947181 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -57,7 +57,7 @@
>  #include "qemu/queue.h"
>  #include "multifd.h"
>  
> -#define MAX_THROTTLE  (32 << 20)      /* Migration transfer speed throttling */
> +#define MAX_THROTTLE  (128 << 20)      /* Migration transfer speed throttling */
>  
>  /* Amount of time to allocate to each "chunk" of bandwidth-throttled
>   * data. */
> -- 
> 2.26.2
> 
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [PATCH] migration: increase max-bandwidth to 128 MiB/s (1 Gib/s)

Posted by Dr. David Alan Gilbert 3 years, 7 months ago

* Laurent Vivier (lvivier@redhat.com) wrote:
> max-bandwidth is set by default to 32 MiB/s (256 Mib/s)
> since 2008 (5bb7910af031c).
> 
> Most of the CPUs can dirty memory faster than that now,
> and this is clearly a problem with POWER where the page
> size is 64 kiB and not 4 KiB.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Thanks,

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

in another 12 years we can increase it by 8x again!

> ---
>  migration/migration.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 58a5452471f9..1c4174947181 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -57,7 +57,7 @@
>  #include "qemu/queue.h"
>  #include "multifd.h"
>  
> -#define MAX_THROTTLE  (32 << 20)      /* Migration transfer speed throttling */
> +#define MAX_THROTTLE  (128 << 20)      /* Migration transfer speed throttling */
>  
>  /* Amount of time to allocate to each "chunk" of bandwidth-throttled
>   * data. */
> -- 
> 2.26.2
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK