RE: [Intel-wired-lan] [PATCH] ixgbe: Limit lowest interrupt rate for adaptive interrupt moderation to 12K

2015-09-10 Thread Singh, Krishneil K 

-Original Message-
From: Intel-wired-lan [mailto:intel-wired-lan-boun...@lists.osuosl.org] On 
Behalf Of Jeff Kirsher
Sent: Wednesday, September 2, 2015 3:07 AM
To: Alexander Duyck <alexander.du...@gmail.com>
Cc: netdev@vger.kernel.org; intel-wired-...@lists.osuosl.org
Subject: Re: [Intel-wired-lan] [PATCH] ixgbe: Limit lowest interrupt rate for 
adaptive interrupt moderation to 12K

On Tue, 2015-09-01 at 18:49 -0700, Alexander Duyck wrote:
> On 07/30/2015 03:19 PM, Alexander Duyck wrote:
> > This patch updates the lowest limit for adaptive interrupt interrupt 
> > moderation to roughly 12K interrupts per second.
> >
> > The way I came about reaching 12K as the desired interrupt rate is
> by
> > testing with UDP flows.  Specifically I had a simple test that ran a 
> > netperf UDP_STREAM test at varying sizes.  What I found was as the
> packet
> > sizes increased the performance fell steadily behind until we were
> only
> > able to receive at ~4Gb/s with a message size of 65507.  A bit of
> digging
> > found that we were dropping packets for the socket in the network
> stack,
> > and looking at things further what I found was I could solve it by
> increasing
> > the interrupt rate, or increasing the rmem_default/rmem_max.  What I
> found was
> > that when the interrupt coalescing resulted in more data being
> processed
> > per interrupt than could be stored in the socket buffer we started
> losing
> > packets and the performance dropped.  So I reached 12K based on the 
> > following math.
> >
> > rmem_default = 212992
> > skb->truesize = 2994
> > 212992 / 2994 = 71.14 packets to fill the buffer
> >
> > packet rate at 1514 packet size is 812744pps
> > 71.14 / 812744 = 87.9us to fill socket buffer
> >
> > >From there it was just a matter of choosing the interrupt rate and
> > providing a bit of wiggle room which is why I decided to go with 12K 
> > interrupts per second as that uses a value of 84us.
> >
> > The data below is based on VM to VM over a direct assigned ixgbe
> interface.
> > The test run was:
> >   netperf -H  -t UDP_STREAM"
> >
> > Socket  Message  Elapsed  Messages   CPU
> Service
> > SizeSize Time Okay Errors   Throughput   Util
> Demand
> > bytes   bytessecs#  #   10^6bits/sec % SS
> us/KB
> > Before:
> > 212992   65507   60.00 1100662  0 9613.4 10.89
> 0.557
> > 212992   60.00  4734744135.4 11.27
> 0.576
> >
> > After:
> > 212992   65507   60.00 1100413  0 9611.2 10.73
> 0.549
> > 212992   60.00  9741328508.3 11.69
> 0.598
> >
> > Using bare metal the data is similar but not as dramatic as the
> throughput
> > increases from about 8.5Gb/s to 9.5Gb/s.
> >
> > Signed-off-by: Alexander Duyck <alexander.h.du...@redhat.com>
> 
> Has there been any update on this patch?  I submitted it just over a 
> month ago now and it hasn't received any feedback.  I was hoping this 
> could be submitted before the merge window closes for net-next.

It will be in the next series I push later today.

Tested-by: Krishneil Singh <krishneil.k.si...@intel.com>

Re: [Intel-wired-lan] [PATCH] ixgbe: Limit lowest interrupt rate for adaptive interrupt moderation to 12K

2015-09-02 Thread Jeff Kirsher 
On Tue, 2015-09-01 at 18:49 -0700, Alexander Duyck wrote:
> On 07/30/2015 03:19 PM, Alexander Duyck wrote:
> > This patch updates the lowest limit for adaptive interrupt interrupt
> > moderation to roughly 12K interrupts per second.
> >
> > The way I came about reaching 12K as the desired interrupt rate is
> by
> > testing with UDP flows.  Specifically I had a simple test that ran a
> > netperf UDP_STREAM test at varying sizes.  What I found was as the
> packet
> > sizes increased the performance fell steadily behind until we were
> only
> > able to receive at ~4Gb/s with a message size of 65507.  A bit of
> digging
> > found that we were dropping packets for the socket in the network
> stack,
> > and looking at things further what I found was I could solve it by
> increasing
> > the interrupt rate, or increasing the rmem_default/rmem_max.  What I
> found was
> > that when the interrupt coalescing resulted in more data being
> processed
> > per interrupt than could be stored in the socket buffer we started
> losing
> > packets and the performance dropped.  So I reached 12K based on the
> > following math.
> >
> > rmem_default = 212992
> > skb->truesize = 2994
> > 212992 / 2994 = 71.14 packets to fill the buffer
> >
> > packet rate at 1514 packet size is 812744pps
> > 71.14 / 812744 = 87.9us to fill socket buffer
> >
> > >From there it was just a matter of choosing the interrupt rate and
> > providing a bit of wiggle room which is why I decided to go with 12K
> > interrupts per second as that uses a value of 84us.
> >
> > The data below is based on VM to VM over a direct assigned ixgbe
> interface.
> > The test run was:
> >   netperf -H  -t UDP_STREAM"
> >
> > Socket  Message  Elapsed  Messages   CPU
> Service
> > SizeSize Time Okay Errors   Throughput   Util
> Demand
> > bytes   bytessecs#  #   10^6bits/sec % SS
> us/KB
> > Before:
> > 212992   65507   60.00 1100662  0 9613.4 10.89
> 0.557
> > 212992   60.00  4734744135.4 11.27
> 0.576
> >
> > After:
> > 212992   65507   60.00 1100413  0 9611.2 10.73
> 0.549
> > 212992   60.00  9741328508.3 11.69
> 0.598
> >
> > Using bare metal the data is similar but not as dramatic as the
> throughput
> > increases from about 8.5Gb/s to 9.5Gb/s.
> >
> > Signed-off-by: Alexander Duyck 
> 
> Has there been any update on this patch?  I submitted it just over a 
> month ago now and it hasn't received any feedback.  I was hoping this 
> could be submitted before the merge window closes for net-next.

It will be in the next series I push later today.


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Re: [Intel-wired-lan] [PATCH] ixgbe: Limit lowest interrupt rate for adaptive interrupt moderation to 12K

2015-09-01 Thread Alexander Duyck 

On 07/30/2015 03:19 PM, Alexander Duyck wrote:

This patch updates the lowest limit for adaptive interrupt interrupt
moderation to roughly 12K interrupts per second.

The way I came about reaching 12K as the desired interrupt rate is by
testing with UDP flows.  Specifically I had a simple test that ran a
netperf UDP_STREAM test at varying sizes.  What I found was as the packet
sizes increased the performance fell steadily behind until we were only
able to receive at ~4Gb/s with a message size of 65507.  A bit of digging
found that we were dropping packets for the socket in the network stack,
and looking at things further what I found was I could solve it by increasing
the interrupt rate, or increasing the rmem_default/rmem_max.  What I found was
that when the interrupt coalescing resulted in more data being processed
per interrupt than could be stored in the socket buffer we started losing
packets and the performance dropped.  So I reached 12K based on the
following math.

rmem_default = 212992
skb->truesize = 2994
212992 / 2994 = 71.14 packets to fill the buffer

packet rate at 1514 packet size is 812744pps
71.14 / 812744 = 87.9us to fill socket buffer

>From there it was just a matter of choosing the interrupt rate and
providing a bit of wiggle room which is why I decided to go with 12K
interrupts per second as that uses a value of 84us.

The data below is based on VM to VM over a direct assigned ixgbe interface.
The test run was:
netperf -H  -t UDP_STREAM"

Socket  Message  Elapsed  Messages   CPU  Service
SizeSize Time Okay Errors   Throughput   Util Demand
bytes   bytessecs#  #   10^6bits/sec % SS us/KB
Before:
212992   65507   60.00 1100662  0 9613.4 10.890.557
212992   60.00  4734744135.4 11.270.576

After:
212992   65507   60.00 1100413  0 9611.2 10.730.549
212992   60.00  9741328508.3 11.690.598

Using bare metal the data is similar but not as dramatic as the throughput
increases from about 8.5Gb/s to 9.5Gb/s.

Signed-off-by: Alexander Duyck 


Has there been any update on this patch?  I submitted it just over a 
month ago now and it hasn't received any feedback.  I was hoping this 
could be submitted before the merge window closes for net-next.


Thanks.

- Alex
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Re: [Intel-wired-lan] [PATCH] ixgbe: Limit lowest interrupt rate for adaptive interrupt moderation to 12K

2015-09-01 Thread Hisashi T Fujinaka 

On Tue, 1 Sep 2015, Alexander Duyck wrote:


On 07/30/2015 03:19 PM, Alexander Duyck wrote:

This patch updates the lowest limit for adaptive interrupt interrupt
moderation to roughly 12K interrupts per second.

...
Has there been any update on this patch?  I submitted it just over a month 
ago now and it hasn't received any feedback.  I was hoping this could be 
submitted before the merge window closes for net-next.


Thanks.


I'm nobody, but it makes sense to me.

--
Hisashi T Fujinaka - ht...@twofifty.com (also todd.fujin...@intel.com)
BSEE + BSChem + BAEnglish + MSCS + $2.50 = coffee
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