diff mbox series

[3/3] net: mhi: Increase the default MTU from 16K to 32K

Message ID 20230606123119.57499-4-manivannan.sadhasivam@linaro.org (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Add MHI Endpoint network driver | expand

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Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Guessed tree name to be net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Manivannan Sadhasivam June 6, 2023, 12:31 p.m. UTC
Most of the Qualcomm endpoint devices are supporting 32K MTU for the
UL (Uplink) and DL (Downlink) channels. So let's use the same value
in the MHI NET driver also. This gives almost 2x increase in the throughput
for the UL channel.

Below is the comparision:

iperf on the UL channel with 16K MTU:

[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec   353 MBytes   296 Mbits/sec

iperf on the UL channel with 32K MTU:

[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec   695 MBytes   583 Mbits/sec

Cc: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/net/mhi_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jeffrey Hugo June 6, 2023, 1:50 p.m. UTC | #1
On 6/6/2023 6:31 AM, Manivannan Sadhasivam wrote:
> Most of the Qualcomm endpoint devices are supporting 32K MTU for the
> UL (Uplink) and DL (Downlink) channels. So let's use the same value
> in the MHI NET driver also. This gives almost 2x increase in the throughput
> for the UL channel.
> 
> Below is the comparision:
> 
> iperf on the UL channel with 16K MTU:
> 
> [ ID] Interval       Transfer     Bandwidth
> [  3]  0.0-10.0 sec   353 MBytes   296 Mbits/sec
> 
> iperf on the UL channel with 32K MTU:
> 
> [ ID] Interval       Transfer     Bandwidth
> [  3]  0.0-10.0 sec   695 MBytes   583 Mbits/sec
> 
> Cc: Loic Poulain <loic.poulain@linaro.org>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>   drivers/net/mhi_net.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
> index 3d322ac4f6a5..eddc2c701da4 100644
> --- a/drivers/net/mhi_net.c
> +++ b/drivers/net/mhi_net.c
> @@ -14,7 +14,7 @@
>   
>   #define MHI_NET_MIN_MTU		ETH_MIN_MTU
>   #define MHI_NET_MAX_MTU		0xffff
> -#define MHI_NET_DEFAULT_MTU	0x4000
> +#define MHI_NET_DEFAULT_MTU	0x8000

Why not SZ_32K?
Manivannan Sadhasivam June 7, 2023, 6:58 a.m. UTC | #2
On Tue, Jun 06, 2023 at 07:50:23AM -0600, Jeffrey Hugo wrote:
> On 6/6/2023 6:31 AM, Manivannan Sadhasivam wrote:
> > Most of the Qualcomm endpoint devices are supporting 32K MTU for the
> > UL (Uplink) and DL (Downlink) channels. So let's use the same value
> > in the MHI NET driver also. This gives almost 2x increase in the throughput
> > for the UL channel.
> > 
> > Below is the comparision:
> > 
> > iperf on the UL channel with 16K MTU:
> > 
> > [ ID] Interval       Transfer     Bandwidth
> > [  3]  0.0-10.0 sec   353 MBytes   296 Mbits/sec
> > 
> > iperf on the UL channel with 32K MTU:
> > 
> > [ ID] Interval       Transfer     Bandwidth
> > [  3]  0.0-10.0 sec   695 MBytes   583 Mbits/sec
> > 
> > Cc: Loic Poulain <loic.poulain@linaro.org>
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> >   drivers/net/mhi_net.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
> > index 3d322ac4f6a5..eddc2c701da4 100644
> > --- a/drivers/net/mhi_net.c
> > +++ b/drivers/net/mhi_net.c
> > @@ -14,7 +14,7 @@
> >   #define MHI_NET_MIN_MTU		ETH_MIN_MTU
> >   #define MHI_NET_MAX_MTU		0xffff
> > -#define MHI_NET_DEFAULT_MTU	0x4000
> > +#define MHI_NET_DEFAULT_MTU	0x8000
> 
> Why not SZ_32K?

Makes sense. Will change it in next iteration.

- Mani
Simon Horman June 7, 2023, 8:21 a.m. UTC | #3
On Tue, Jun 06, 2023 at 06:01:19PM +0530, Manivannan Sadhasivam wrote:
> Most of the Qualcomm endpoint devices are supporting 32K MTU for the
> UL (Uplink) and DL (Downlink) channels. So let's use the same value
> in the MHI NET driver also. This gives almost 2x increase in the throughput
> for the UL channel.
> 
> Below is the comparision:

Hi Manivannan,

as it looks like there will be a v2: comparision -> comparison

...
Andrew Lunn June 7, 2023, 12:25 p.m. UTC | #4
On Wed, Jun 07, 2023 at 12:28:09PM +0530, Manivannan Sadhasivam wrote:
> On Tue, Jun 06, 2023 at 07:50:23AM -0600, Jeffrey Hugo wrote:
> > On 6/6/2023 6:31 AM, Manivannan Sadhasivam wrote:
> > > Most of the Qualcomm endpoint devices are supporting 32K MTU for the
> > > UL (Uplink) and DL (Downlink) channels. So let's use the same value
> > > in the MHI NET driver also. This gives almost 2x increase in the throughput
> > > for the UL channel.

You say here 'Most'. What happens on those which do not support 32K?
Do the packets get dropped and it turns into a black hole?

   Andrew
Manivannan Sadhasivam June 7, 2023, 2:56 p.m. UTC | #5
On Wed, Jun 07, 2023 at 02:25:50PM +0200, Andrew Lunn wrote:
> On Wed, Jun 07, 2023 at 12:28:09PM +0530, Manivannan Sadhasivam wrote:
> > On Tue, Jun 06, 2023 at 07:50:23AM -0600, Jeffrey Hugo wrote:
> > > On 6/6/2023 6:31 AM, Manivannan Sadhasivam wrote:
> > > > Most of the Qualcomm endpoint devices are supporting 32K MTU for the
> > > > UL (Uplink) and DL (Downlink) channels. So let's use the same value
> > > > in the MHI NET driver also. This gives almost 2x increase in the throughput
> > > > for the UL channel.
> 
> You say here 'Most'. What happens on those which do not support 32K?
> Do the packets get dropped and it turns into a black hole?
> 

Yeah, and the host has to retransmit. But I checked again with Qcom on the MTU
size and got a different answer that forced me to change "most" to "few". So
this patch is not needed for now. I'll drop it.

- Mani

>    Andrew
>
diff mbox series

Patch

diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
index 3d322ac4f6a5..eddc2c701da4 100644
--- a/drivers/net/mhi_net.c
+++ b/drivers/net/mhi_net.c
@@ -14,7 +14,7 @@ 
 
 #define MHI_NET_MIN_MTU		ETH_MIN_MTU
 #define MHI_NET_MAX_MTU		0xffff
-#define MHI_NET_DEFAULT_MTU	0x4000
+#define MHI_NET_DEFAULT_MTU	0x8000
 
 struct mhi_net_stats {
 	u64_stats_t rx_packets;