Hi,
Below are the results of the CPU utilization for 82571 and
82574(MSI-X) chips.
Test Setup
netperf client --> Server with 82571 and 82574 chip.
Current PPS: 4,50,000
Server config
Kernel: Vanilla 2.6.39.4
CPU: Affinity is binded to a
single core of Intel Quad core Q9400 2.66 Ghz processor.
e1000e Driver: 1.9.5
(netperf -t UDP_STREAM -N -l 3600 -H <server ip> -- -m 64)
1.) 82571 and 82574 with InterruptThrottleRate=3
interrupts idle cpu
82571 21100 52-54
82574 21100 62-64
2.) 82571 and 82574 with InterruptThrottleRate=3000
interrupts idle cpu
82571 4050 62-64 (10% gain
compare to InterruptThrottleRate=3)
82574 4050 63-65 (1% gain
compare to InterruptThrottleRate=3)
3.) 82571 and 82574 with InterruptThrottleRate=8000
interrupts idle cpu
82571 9050 60-62 (8% gain compare
to InterruptThrottleRate=3)
82574 9050 63-65 (1% gain compare
to InterruptThrottleRate=3)
I see less number of interrupts with MSI-X interrupts but CPU
utilization is almost same.
Is it possible to reduce CPU utilization further by
tunning/changing any other parameters ?
Rgds,
Nishit Shah.
On 6/26/2012 2:32 PM, Nishit Shah wrote:
Hi Mathew,
It is working fine for both the reported issues.
Thanks once again for all your help.
I have prepared a box with 2 82571 ports and 2 82574 ports.
Will let you know the CPU utilization results of simplified mode
for both the chips.
Rgds,
Nishit Shah.
On 6/23/2012 5:53 AM, Vick, Matthew wrote:
(Top-posting)
I sent you a tar ball of a patched 1.9.5 e1000e that should resolve
both of the issues you're seeing. Please let me know if you have any
problems with it.
Cheers,
Matthew
*From:*Nishit Shah [mailto:[email protected]]
*Sent:* Tuesday, June 19, 2012 10:33 PM
*To:* Vick, Matthew
*Cc:* [email protected]
*Subject:* Re: [E1000-devel] problem with simplified balancing on
82574 chips
Thanks Mathew,
It really helps a lot in understanding the workings.
Rgds,
Nishit Shah.
On 6/20/2012 6:27 AM, Vick, Matthew wrote:
(Top-posting)
Thanks for the additional data. 82574, being a newer part, has a more
efficient interrupt mechanism for the driver to use than previous
parts. The restriction on interrupts with InterruptThrottleRate
obviously helps CPU utilization, but it isn't going to be as dramatic
of a change when compared to other parts the interrupts are already
more efficient.
I'm still working to create a finalized patch that resolves both
issues you've raised.
Cheers,
Matthew
*From:*Nishit Shah [mailto:[email protected]]
*Sent:* Tuesday, June 19, 2012 5:47 AM
*To:* Vick, Matthew
*Cc:* [email protected]
<mailto:[email protected]>
*Subject:* Re: [E1000-devel] problem with simplified balancing on
82574 chips
Hi Matthew,
1.) vmstat and top output with ethtool -C <nic> rx-usecs 0 as
well as ethtool -C <nic> rx-usecs 3. (In my case both are giving me
the same results)
# vmstat 1
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
r b swpd free buff cache si so bi bo
in cs us sy id wa st
0 0 0 2013040 11748 5736 0 0 0 0 40644
18 0 23 77 0 0
0 0 0 2013040 11748 5736 0 0 0 0 40736
28 0 23 77 0 0
0 0 0 2013040 11748 5736 0 0 0 0 40730
10 0 24 76 0 0
0 0 0 2013040 11748 5736 0 0 0 0 40731
14 0 24 76 0 0
0 0 0 2013040 11748 5736 0 0 0 0 40735
24 0 24 76 0 0
0 0 0 2013040 11748 5736 0 0 0 0 40732
12 0 24 76 0 0
# top output
Tasks: 41 total, 1 running, 40 sleeping, 0 stopped, 0 zombie
Cpu0 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi,
0.0%si, 0.0%st
Cpu1 : 0.0%us, 0.0%sy, 0.0%ni, *52.8%id,* 0.0%wa, 1.3%hi,
*45.8%si,* 0.0%st
2.) vmstat and top output with ethtool -C <nic> rx-usecs 4
# vmstat 1
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
r b swpd free buff cache si so bi bo
in cs us sy id wa st
0 0 0 2012916 11804 5740 0 0 0 0 18599
20 0 23 77 0 0
0 0 0 2012916 11804 5740 0 0 0 0 18588
14 0 22 78 0 0
0 0 0 2012916 11804 5740 0 0 0 0 18592
12 0 22 78 0 0
0 0 0 2012916 11804 5740 0 0 0 0 18591
12 0 22 78 0 0
0 0 0 2012916 11804 5740 0 0 0 0 18593
11 0 22 78 0 0
0 0 0 2012916 11804 5740 0 0 0 0 18594
12 0 23 77 0 0
# top output
Tasks: 41 total, 1 running, 40 sleeping, 0 stopped, 0 zombie
Cpu0 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi,
0.0%si, 0.0%st
Cpu1 : 0.0%us, 0.0%sy, 0.0%ni, *53.3%id*, 0.0%wa, 0.3%hi,
*46.3%si*, 0.0%st
I can see a good amount of drop in interrupts in vmstat. i.e. 40600
to 18600 but I don't see much improvement in top output in terms of
CPU utilization.
Rgds,
Nishit Shah.
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