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Date: Fri, 22 Sep 2017 11:22:51 +0100
From: Stefan Hajnoczi <stefanha@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] migration: disable auto-converge during
 bulk block migration
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To: Peter Lieven <pl@kamp.de>
Cc: qemu-devel@nongnu.org, quintela@redhat.com, famz@redhat.com, dgilbert@redhat.com, pbonzini@redhat.com, qemu-stable@nongnu.org

On Thu, Sep 21, 2017 at 02:32:32PM +0200, Peter Lieven wrote:
> auto-converge and block migration currently do not play well together.
> During block migration the auto-converge logic detects that ram
> migration makes no progress and thus throttles down the vm until
> it nearly stalls completely. Avoid this by disabling the throttling
> logic during the bulk phase of the block migration.

Please include the rationale in a comment here:

> -        if (migrate_auto_converge()) {
> +        if (migrate_auto_converge() && !blk_mig_bulk_active()) {

That way it's clear why auto-converge isn't enabled when block migration
is active.