On Tue, Jun 21, 2022 at 04:51:39PM +0200, Juan Quintela wrote:
> > IIRC, the kernel will fall back to copying only if the network adapter /
> > driver
> > does not support MSG_ZEROCOPY, like when it does not support scatter-gather.
>
> My understanding is that it will fallback when you have too m
On Tue, Jun 21, 2022 at 12:35:54AM -0300, Leonardo Brás wrote:
> > This reminded me - Leo, have you considered adding the patch altogether to
> > detect the "fallback to non-zero-copy" condition? Because when with it and
> > when the fallback happens at some point (e.g. when the guest memory is
>
Leonardo Brás wrote:
> On Mon, 2022-06-20 at 11:44 -0400, Peter Xu wrote:
>> On Mon, Jun 20, 2022 at 11:23:53AM +0200, Juan Quintela wrote:
>> > Once discussed this, what I asked in the past is that you are having too
>> > much dirty memory on zero_copy. When you have a Multiterabyte guest, in
>>
On Mon, 2022-06-20 at 11:44 -0400, Peter Xu wrote:
> On Mon, Jun 20, 2022 at 11:23:53AM +0200, Juan Quintela wrote:
> > Once discussed this, what I asked in the past is that you are having too
> > much dirty memory on zero_copy. When you have a Multiterabyte guest, in
> > a single round you have a
On Mon, 2022-06-20 at 11:23 +0200, Juan Quintela wrote:
> Leonardo Bras wrote:
> > When sending memory pages with MSG_ZEROCOPY, it's necessary to flush
> > to make sure all dirty pages are sent before a future version of them
> > happens to be sent.
> >
> > Currently, the flush happens every time
On Mon, Jun 20, 2022 at 11:23:53AM +0200, Juan Quintela wrote:
> Once discussed this, what I asked in the past is that you are having too
> much dirty memory on zero_copy. When you have a Multiterabyte guest, in
> a single round you have a "potentially" dirty memory on each channel of:
>
>tot
Leonardo Bras wrote:
> When sending memory pages with MSG_ZEROCOPY, it's necessary to flush
> to make sure all dirty pages are sent before a future version of them
> happens to be sent.
>
> Currently, the flush happens every time at the end of ram_save_iterate(),
> which usually happens around 20x
When sending memory pages with MSG_ZEROCOPY, it's necessary to flush
to make sure all dirty pages are sent before a future version of them
happens to be sent.
Currently, the flush happens every time at the end of ram_save_iterate(),
which usually happens around 20x per second, due to a timeout.
C
