* [PATCH net-next] vhost_net: disable zerocopy by default
@ 2019-06-17 9:20 Jason Wang
2019-06-17 14:43 ` Michael S. Tsirkin
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Jason Wang @ 2019-06-17 9:20 UTC (permalink / raw)
To: jasowang, mst, kvm, virtualization, netdev, linux-kernel; +Cc: huhai
Vhost_net was known to suffer from HOL[1] issues which is not easy to
fix. Several downstream disable the feature by default. What's more,
the datapath was split and datacopy path got the support of batching
and XDP support recently which makes it faster than zerocopy part for
small packets transmission.
It looks to me that disable zerocopy by default is more
appropriate. It cold be enabled by default again in the future if we
fix the above issues.
[1] https://patchwork.kernel.org/patch/3787671/
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/net.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 2d9df786a9d3..21e0805e5e60 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -36,7 +36,7 @@
#include "vhost.h"
-static int experimental_zcopytx = 1;
+static int experimental_zcopytx = 0;
module_param(experimental_zcopytx, int, 0444);
MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
" 1 -Enable; 0 - Disable");
--
2.18.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH net-next] vhost_net: disable zerocopy by default
2019-06-17 9:20 [PATCH net-next] vhost_net: disable zerocopy by default Jason Wang
@ 2019-06-17 14:43 ` Michael S. Tsirkin
2019-06-17 14:43 ` Michael S. Tsirkin
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2019-06-17 14:43 UTC (permalink / raw)
To: Jason Wang; +Cc: netdev, huhai, linux-kernel, kvm, virtualization
On Mon, Jun 17, 2019 at 05:20:54AM -0400, Jason Wang wrote:
> Vhost_net was known to suffer from HOL[1] issues which is not easy to
> fix. Several downstream disable the feature by default. What's more,
> the datapath was split and datacopy path got the support of batching
> and XDP support recently which makes it faster than zerocopy part for
> small packets transmission.
>
> It looks to me that disable zerocopy by default is more
> appropriate. It cold be enabled by default again in the future if we
> fix the above issues.
>
> [1] https://patchwork.kernel.org/patch/3787671/
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/vhost/net.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 2d9df786a9d3..21e0805e5e60 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -36,7 +36,7 @@
>
> #include "vhost.h"
>
> -static int experimental_zcopytx = 1;
> +static int experimental_zcopytx = 0;
> module_param(experimental_zcopytx, int, 0444);
> MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
> " 1 -Enable; 0 - Disable");
> --
> 2.18.1
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net-next] vhost_net: disable zerocopy by default
2019-06-17 9:20 [PATCH net-next] vhost_net: disable zerocopy by default Jason Wang
2019-06-17 14:43 ` Michael S. Tsirkin
@ 2019-06-17 14:43 ` Michael S. Tsirkin
2019-06-17 20:58 ` David Miller
2019-06-17 20:58 ` David Miller
3 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2019-06-17 14:43 UTC (permalink / raw)
To: Jason Wang; +Cc: kvm, virtualization, netdev, linux-kernel, huhai
On Mon, Jun 17, 2019 at 05:20:54AM -0400, Jason Wang wrote:
> Vhost_net was known to suffer from HOL[1] issues which is not easy to
> fix. Several downstream disable the feature by default. What's more,
> the datapath was split and datacopy path got the support of batching
> and XDP support recently which makes it faster than zerocopy part for
> small packets transmission.
>
> It looks to me that disable zerocopy by default is more
> appropriate. It cold be enabled by default again in the future if we
> fix the above issues.
>
> [1] https://patchwork.kernel.org/patch/3787671/
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/vhost/net.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 2d9df786a9d3..21e0805e5e60 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -36,7 +36,7 @@
>
> #include "vhost.h"
>
> -static int experimental_zcopytx = 1;
> +static int experimental_zcopytx = 0;
> module_param(experimental_zcopytx, int, 0444);
> MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
> " 1 -Enable; 0 - Disable");
> --
> 2.18.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] vhost_net: disable zerocopy by default
2019-06-17 9:20 [PATCH net-next] vhost_net: disable zerocopy by default Jason Wang
2019-06-17 14:43 ` Michael S. Tsirkin
2019-06-17 14:43 ` Michael S. Tsirkin
@ 2019-06-17 20:58 ` David Miller
2019-06-17 20:58 ` David Miller
3 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2019-06-17 20:58 UTC (permalink / raw)
To: jasowang; +Cc: kvm, mst, netdev, linux-kernel, virtualization, huhai
From: Jason Wang <jasowang@redhat.com>
Date: Mon, 17 Jun 2019 05:20:54 -0400
> Vhost_net was known to suffer from HOL[1] issues which is not easy to
> fix. Several downstream disable the feature by default. What's more,
> the datapath was split and datacopy path got the support of batching
> and XDP support recently which makes it faster than zerocopy part for
> small packets transmission.
>
> It looks to me that disable zerocopy by default is more
> appropriate. It cold be enabled by default again in the future if we
> fix the above issues.
>
> [1] https://patchwork.kernel.org/patch/3787671/
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Applied, thanks Jason.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] vhost_net: disable zerocopy by default
2019-06-17 9:20 [PATCH net-next] vhost_net: disable zerocopy by default Jason Wang
` (2 preceding siblings ...)
2019-06-17 20:58 ` David Miller
@ 2019-06-17 20:58 ` David Miller
3 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2019-06-17 20:58 UTC (permalink / raw)
To: jasowang; +Cc: mst, kvm, virtualization, netdev, linux-kernel, huhai
From: Jason Wang <jasowang@redhat.com>
Date: Mon, 17 Jun 2019 05:20:54 -0400
> Vhost_net was known to suffer from HOL[1] issues which is not easy to
> fix. Several downstream disable the feature by default. What's more,
> the datapath was split and datacopy path got the support of batching
> and XDP support recently which makes it faster than zerocopy part for
> small packets transmission.
>
> It looks to me that disable zerocopy by default is more
> appropriate. It cold be enabled by default again in the future if we
> fix the above issues.
>
> [1] https://patchwork.kernel.org/patch/3787671/
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Applied, thanks Jason.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH net-next] vhost_net: disable zerocopy by default
@ 2019-06-17 9:20 Jason Wang
0 siblings, 0 replies; 6+ messages in thread
From: Jason Wang @ 2019-06-17 9:20 UTC (permalink / raw)
To: jasowang, mst, kvm, virtualization, netdev, linux-kernel; +Cc: huhai
Vhost_net was known to suffer from HOL[1] issues which is not easy to
fix. Several downstream disable the feature by default. What's more,
the datapath was split and datacopy path got the support of batching
and XDP support recently which makes it faster than zerocopy part for
small packets transmission.
It looks to me that disable zerocopy by default is more
appropriate. It cold be enabled by default again in the future if we
fix the above issues.
[1] https://patchwork.kernel.org/patch/3787671/
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/net.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 2d9df786a9d3..21e0805e5e60 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -36,7 +36,7 @@
#include "vhost.h"
-static int experimental_zcopytx = 1;
+static int experimental_zcopytx = 0;
module_param(experimental_zcopytx, int, 0444);
MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
" 1 -Enable; 0 - Disable");
--
2.18.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-06-17 20:58 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2019-06-17 9:20 [PATCH net-next] vhost_net: disable zerocopy by default Jason Wang
2019-06-17 14:43 ` Michael S. Tsirkin
2019-06-17 14:43 ` Michael S. Tsirkin
2019-06-17 20:58 ` David Miller
2019-06-17 20:58 ` David Miller
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2019-06-17 9:20 Jason Wang
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