Re: [PATCH 4/4] multifd: reset next_packet_len after sending pages

[Fabiano Rosas]

Elena Ufimtseva <elena.ufimtseva@oracle.com> writes:

> Sometimes multifd sends just sync packet with no pages
> (normal_num is 0). In this case the old value is being
> preserved and being accounted for while only packet_len
> is being transferred.
> Reset it to 0 after sending and accounting for.
>
> TODO: Fix the same packet ids in the stream.
> with this patch, there is still an issue with the duplicated
> packets ids being sent (with different number of pages/flags).
> See in below multifd_send trace (before this change):
> multifd_send 394.774 pid=55477 id=0x1 packet_num=0x6f0 normal=0x57 flags=0x1 
> next_packet_size=0x57000
> multifd_send 181.244 pid=55477 id=0x1 packet_num=0x6f0 normal=0x0 flags=0x0 
> next_packet_size=0x57000
>
> With this commit there are still duplicated packets, but since no pages
> are being sent with sync flag set, next_packet_size is 0:
> multifd_send 27.814 pid=18602 id=0x1 packet_num=0x574 normal=0x7b flags=0x1 
> next_packet_size=0x7b000
> multifd_send 136054.792 pid=18602 id=0x1 packet_num=0x574 normal=0x0 
> flags=0x0 next_packet_size=0x0
> If there is a suggestion how to fix this properly, I will be
> glad to use it.
>
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> ---
>  migration/multifd.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/migration/multifd.c b/migration/multifd.c
> index 3281397b18..8b4e26051b 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -730,6 +730,7 @@ static void *multifd_send_thread(void *opaque)
>                         p->next_packet_size + p->packet_len);
>              stat64_add(&mig_stats.transferred,
>                         p->next_packet_size + p->packet_len);
> +            p->next_packet_size = 0;
>              qemu_mutex_lock(&p->mutex);
>              p->pending_job--;
>              qemu_mutex_unlock(&p->mutex);

Reviewed-by: Fabiano Rosas <farosas@suse.de>