Re: [Iperf-users] iperf3: abrupt interval issue

[Bruce A. Mah]

If memory serves me right, Bob McMahon wrote:
> The first sample shows 37.7Mb/s for iperf3 and 87.0 Mb/s for iperf2
> which is quite a big difference.

That is a significant difference, indeed.  However in the original
email, the iperf3 throughput was 87.6 Mbps measured at the receiver.
I'm puzzled about the difference between the different iperf3 measurements.

I wonder if we could also learn something more by seeing a dump of JSON
output from the iperf3 client (this can be gotten by the -J command-line
flag given to the client).

> Nikita, it would be good to show more samples (maybe all of them?) as
> well as both the client and server outputs.  Also, to follow the TCP
> ramp up w/iperf2 make a run setting -i to 0.01 (or 0.005) and the time
> -t to 2 seconds.  Again, use -e on both the server and the client.   All
> possible information helps. 
> 
> Note: I'm not sure if iperf3 uses setitimer
>  or not nor if this platform
> supports clock_gettime  but
> here is a short timer program
> 
> which I use to verify timing (as well as timely reporting over ssh
> pipes.)  One can compile and run this on a  platform to verify the
> itimer fires as expected.

iperf3 uses gettimeofday(3) for timing.  I know this isn't exactly
optimal but it's portable.  I think we have an enhancement request open
to use something better.

Bruce.

> On Tue, May 8, 2018 at 9:16 AM, Bruce A. Mah  > wrote:
> 
> If memory serves me right, Bob McMahon wrote:
> > Hi Nikita,
> > 
> > I don't know the iperf3 code.  We've been maintaining iperf2 mostly per
> > WiFi testing needs.  Bruce's original response suggested internal timers
> > not firing on time.
> 
> Sorry for the radio silence...yes I think this is still the case with
> iperf3, although I don't know *why* the timers aren't getting processed
> at the desired time.  I haven't come up with a good avenue for
> investigating this yet.
> 
> I would guess that the overall statistics are likely correct, just that
> they don't look pretty.
> 
> Bruce.
> 
> > On Tue, May 8, 2018 at 12:26 AM, Nikita Gupta  
> > >> wrote:
> >
> >     Yes, iperf2 giving correct result. But can you explain why
> *iperf3*
> >     is not showing data of 1 Sec but of 1.24 sec?
> > 
> >     On Tue, 8 May 2018 at 10:37 AM, Bob McMahon
> >     
> >>
> wrote:
> > 
> >         iperf2 seems to be indicating 83 socket writes per second with
> >         no write errors.  The congestion window is 42K and the RTT is
> >         3.5 milliseconds.  Nothing seems too unusual to me.
> > 
> >         Bob
> > 
> >         On Mon, May 7, 2018 at 8:05 PM, Nikita Gupta
> >         
> >> wrote:
> > 
> >             Yeah Bob,
> > 
> >             Input command for iperf 2.0.10:
> >             iperf -c  -e -i 1 -t 10
> >             Output for iperf 2.0.10:
> >             [  3] 0.00-1.00 sec  10.4 MBytes  87.0 Mbits/sec 
> >             83/0  0   42K/3464 us
> > 
> >             input for iperf3:
> >             iperf3 -c  -i 1 -t 10
> >             Output for iperf3:
> >             [  5]   0.00-1.24   sec  5.60 MBytes  37.7 Mbits/sec    0  
> >             38.2 KBytes
> > 
> >             I'm facing issue of time interval with iperf3.
> > 
> >             On Mon, May 7, 2018 at 9:10 PM, Bob McMahon
> >                >>
> >             wrote:
> > 
> >                 The client output for 2.0.10 with -e  and -i 1 could
> >                 provide useful information.
> > 
> >                 Bob
> > 
> >                 On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta
> >                 
> >> wrote:
> > 
> >                     Hi Bob,
> > 
> >                     Working without issue: iperf-2.0.10
> >                     Time interval issue: iperf-3.3, iperf-3.1,
> >                     iperf-3.5, iperf-3.0
> > 
> >                     Regards,
> >                     Nikita
> > 
> >                     On Sat, May 5, 2018 at 3:37 AM, Bob McMahon
> >                

Re: [Iperf-users] iperf3: abrupt interval issue

[Bruce A. Mah]

If memory serves me right, Bob McMahon wrote:
> Hi Nikita,
> 
> I don't know the iperf3 code.  We've been maintaining iperf2 mostly per
> WiFi testing needs.  Bruce's original response suggested internal timers
> not firing on time.

Sorry for the radio silence...yes I think this is still the case with
iperf3, although I don't know *why* the timers aren't getting processed
at the desired time.  I haven't come up with a good avenue for
investigating this yet.

I would guess that the overall statistics are likely correct, just that
they don't look pretty.

Bruce.

> On Tue, May 8, 2018 at 12:26 AM, Nikita Gupta  > wrote:
> 
> Yes, iperf2 giving correct result. But can you explain why *iperf3*
> is not showing data of 1 Sec but of 1.24 sec?
> 
> On Tue, 8 May 2018 at 10:37 AM, Bob McMahon
> > wrote:
> 
> iperf2 seems to be indicating 83 socket writes per second with
> no write errors.  The congestion window is 42K and the RTT is
> 3.5 milliseconds.  Nothing seems too unusual to me.
> 
> Bob
> 
> On Mon, May 7, 2018 at 8:05 PM, Nikita Gupta
> > wrote:
> 
> Yeah Bob,
> 
> Input command for iperf 2.0.10:
> iperf -c  -e -i 1 -t 10
> Output for iperf 2.0.10:
> [  3] 0.00-1.00 sec  10.4 MBytes  87.0 Mbits/sec 
> 83/0  0   42K/3464 us
> 
> input for iperf3:
> iperf3 -c  -i 1 -t 10
> Output for iperf3:
> [  5]   0.00-1.24   sec  5.60 MBytes  37.7 Mbits/sec    0  
> 38.2 KBytes
> 
> I'm facing issue of time interval with iperf3.
> 
> On Mon, May 7, 2018 at 9:10 PM, Bob McMahon
> >
> wrote:
> 
> The client output for 2.0.10 with -e  and -i 1 could
> provide useful information.
> 
> Bob
> 
> On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta
> > wrote:
> 
> Hi Bob,
> 
> Working without issue: iperf-2.0.10
> Time interval issue: iperf-3.3, iperf-3.1,
> iperf-3.5, iperf-3.0
> 
> Regards,
> Nikita
> 
> On Sat, May 5, 2018 at 3:37 AM, Bob McMahon
>  > wrote:
> 
> what version of iperf did you use?  iperf -v
> should provide that.
> 
> If it's a later version of iperf2 the output on
> the client of with the -e option could be helpful.
> 
> Bob
> 
> On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta
>  > wrote:
> 
> Hi Bruce thanks for giving time on this issue.
> 
> I am working on an embedded system with imx50.
> Server i'm using is RaspberryPi. Both the
> machines are connected on same network.
> 
> Yes the system is a bit loaded. So this
> might be the reason.
> But if I reduce the window size then
> bandwidth also reduces and the time interval
> issue disappears.
> 
> But with bandwidth of ~45M (which is the max
> it is showing) then it starts giving time
> interval issues.
> 
> One more thing, I tried with iperf as well
> and its not giving any such issues on same
> machine with same server.
> 
> On Thu, May 3, 2018 at 11:49 PM, Bruce A.
> Mah > wrote:
> 
> If memory serves me right, Nikita Gupta
> wrote:
> > Hi team,
> >
> > While checking network performance
> using iperf3, I'm facing interval
> > issue at client end. Below are the logs:
> >
> > [  5]   0.00-1.05   sec  11.2 MBytes 
> 88.7 Mbits/sec    0   42.4
> 

Re: [Iperf-users] iperf3: abrupt interval issue

[Bob McMahon via Iperf-users]

Hi Nikita,

I don't know the iperf3 code.  We've been maintaining iperf2 mostly per
WiFi testing needs.  Bruce's original response suggested internal timers
not firing on time.

Bob

On Tue, May 8, 2018 at 12:26 AM, Nikita Gupta  wrote:

> Yes, iperf2 giving correct result. But can you explain why *iperf3* is
> not showing data of 1 Sec but of 1.24 sec?
>
> On Tue, 8 May 2018 at 10:37 AM, Bob McMahon 
> wrote:
>
>> iperf2 seems to be indicating 83 socket writes per second with no write
>> errors.  The congestion window is 42K and the RTT is 3.5 milliseconds.
>> Nothing seems too unusual to me.
>>
>> Bob
>>
>> On Mon, May 7, 2018 at 8:05 PM, Nikita Gupta 
>> wrote:
>>
>>> Yeah Bob,
>>>
>>> Input command for iperf 2.0.10:
>>> iperf -c  -e -i 1 -t 10
>>> Output for iperf 2.0.10:
>>> [  3] 0.00-1.00 sec  10.4 MBytes  87.0 Mbits/sec  83/0  0
>>> 42K/3464 us
>>>
>>> input for iperf3:
>>> iperf3 -c  -i 1 -t 10
>>> Output for iperf3:
>>> [  5]   0.00-1.24   sec  5.60 MBytes  37.7 Mbits/sec0   38.2 KBytes
>>>
>>> I'm facing issue of time interval with iperf3.
>>>
>>> On Mon, May 7, 2018 at 9:10 PM, Bob McMahon 
>>> wrote:
>>>
 The client output for 2.0.10 with -e  and -i 1 could provide useful
 information.

 Bob

 On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta 
 wrote:

> Hi Bob,
>
> Working without issue: iperf-2.0.10
> Time interval issue: iperf-3.3, iperf-3.1, iperf-3.5, iperf-3.0
>
> Regards,
> Nikita
>
> On Sat, May 5, 2018 at 3:37 AM, Bob McMahon 
> wrote:
>
>> what version of iperf did you use?  iperf -v should provide that.
>>
>> If it's a later version of iperf2 the output on the client of with
>> the -e option could be helpful.
>>
>> Bob
>>
>> On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta 
>> wrote:
>>
>>> Hi Bruce thanks for giving time on this issue.
>>>
>>> I am working on an embedded system with imx50.
>>> Server i'm using is RaspberryPi. Both the machines are connected on
>>> same network.
>>>
>>> Yes the system is a bit loaded. So this might be the reason.
>>> But if I reduce the window size then bandwidth also reduces and the
>>> time interval issue disappears.
>>>
>>> But with bandwidth of ~45M (which is the max it is showing) then it
>>> starts giving time interval issues.
>>>
>>> One more thing, I tried with iperf as well and its not giving any
>>> such issues on same machine with same server.
>>>
>>> On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:
>>>
 If memory serves me right, Nikita Gupta wrote:
 > Hi team,
 >
 > While checking network performance using iperf3, I'm facing
 interval
 > issue at client end. Below are the logs:
 >
 > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
 > KBytes
 > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
 > KBytes
 > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
 > KBytes
 > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
 > KBytes
 > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
 > KBytes
 > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
 > KBytes
 > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
 > KBytes
 > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
 > KBytes
 > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
 > KBytes
 > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
 > KBytes
 > - - - - - - - - - - - - - - - - - - - - - - - - -
 > [ ID] Interval   Transfer Bitrate Retr
 > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec
 0 sender
 > [  5]   0.00-10.12  sec   106 MBytes  87.6
 Mbits/sec
 > receiver
 >
 > I checked github bug #125 which was addressing this specific
 issue. But
 > no help.
 > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all
 versions,
 > I'm getting the same issue.
 >
 > P.S. Server(with same iperf3 version) provides result as expected
 with 1
 > sec time interval, but client provides data at different time
 intervals
 > in every iteration.
 > Kindly look into the issue and do let me know if m missing
 something.

 What are the command line arguments you are using (both client and
 server side, sanitize them as necessary0?  Also 

Re: [Iperf-users] iperf3: abrupt interval issue

[Nikita Gupta]

Yes, iperf2 giving correct result. But can you explain why *iperf3* is not
showing data of 1 Sec but of 1.24 sec?

On Tue, 8 May 2018 at 10:37 AM, Bob McMahon 
wrote:

> iperf2 seems to be indicating 83 socket writes per second with no write
> errors.  The congestion window is 42K and the RTT is 3.5 milliseconds.
> Nothing seems too unusual to me.
>
> Bob
>
> On Mon, May 7, 2018 at 8:05 PM, Nikita Gupta  wrote:
>
>> Yeah Bob,
>>
>> Input command for iperf 2.0.10:
>> iperf -c  -e -i 1 -t 10
>> Output for iperf 2.0.10:
>> [  3] 0.00-1.00 sec  10.4 MBytes  87.0 Mbits/sec  83/0  0
>> 42K/3464 us
>>
>> input for iperf3:
>> iperf3 -c  -i 1 -t 10
>> Output for iperf3:
>> [  5]   0.00-1.24   sec  5.60 MBytes  37.7 Mbits/sec0   38.2 KBytes
>>
>> I'm facing issue of time interval with iperf3.
>>
>> On Mon, May 7, 2018 at 9:10 PM, Bob McMahon 
>> wrote:
>>
>>> The client output for 2.0.10 with -e  and -i 1 could provide useful
>>> information.
>>>
>>> Bob
>>>
>>> On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta 
>>> wrote:
>>>
 Hi Bob,

 Working without issue: iperf-2.0.10
 Time interval issue: iperf-3.3, iperf-3.1, iperf-3.5, iperf-3.0

 Regards,
 Nikita

 On Sat, May 5, 2018 at 3:37 AM, Bob McMahon 
 wrote:

> what version of iperf did you use?  iperf -v should provide that.
>
> If it's a later version of iperf2 the output on the client of with the
> -e option could be helpful.
>
> Bob
>
> On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta 
> wrote:
>
>> Hi Bruce thanks for giving time on this issue.
>>
>> I am working on an embedded system with imx50.
>> Server i'm using is RaspberryPi. Both the machines are connected on
>> same network.
>>
>> Yes the system is a bit loaded. So this might be the reason.
>> But if I reduce the window size then bandwidth also reduces and the
>> time interval issue disappears.
>>
>> But with bandwidth of ~45M (which is the max it is showing) then it
>> starts giving time interval issues.
>>
>> One more thing, I tried with iperf as well and its not giving any
>> such issues on same machine with same server.
>>
>> On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:
>>
>>> If memory serves me right, Nikita Gupta wrote:
>>> > Hi team,
>>> >
>>> > While checking network performance using iperf3, I'm facing
>>> interval
>>> > issue at client end. Below are the logs:
>>> >
>>> > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
>>> > KBytes
>>> > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
>>> > KBytes
>>> > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
>>> > KBytes
>>> > - - - - - - - - - - - - - - - - - - - - - - - - -
>>> > [ ID] Interval   Transfer Bitrate Retr
>>> > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec
>>> 0 sender
>>> > [  5]   0.00-10.12  sec   106 MBytes  87.6
>>> Mbits/sec
>>> > receiver
>>> >
>>> > I checked github bug #125 which was addressing this specific
>>> issue. But
>>> > no help.
>>> > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all
>>> versions,
>>> > I'm getting the same issue.
>>> >
>>> > P.S. Server(with same iperf3 version) provides result as expected
>>> with 1
>>> > sec time interval, but client provides data at different time
>>> intervals
>>> > in every iteration.
>>> > Kindly look into the issue and do let me know if m missing
>>> something.
>>>
>>> What are the command line arguments you are using (both client and
>>> server side, sanitize them as necessary0?  Also could you say
>>> something
>>> about the environment you're running in?  In particular, what OS and
>>> hardware on the client and server, and what kind of network path are
>>> you
>>> going over?
>>>
>>> I rarely see issues like this (where the statistics printing
>>> intervals
>>> are not aligned to whole second boundaries) in the middle of a test,
>>> 

Re: [Iperf-users] iperf3: abrupt interval issue

[Bob McMahon via Iperf-users]

iperf2 seems to be indicating 83 socket writes per second with no write
errors.  The congestion window is 42K and the RTT is 3.5 milliseconds.
Nothing seems too unusual to me.

Bob

On Mon, May 7, 2018 at 8:05 PM, Nikita Gupta  wrote:

> Yeah Bob,
>
> Input command for iperf 2.0.10:
> iperf -c  -e -i 1 -t 10
> Output for iperf 2.0.10:
> [  3] 0.00-1.00 sec  10.4 MBytes  87.0 Mbits/sec  83/0  0
> 42K/3464 us
>
> input for iperf3:
> iperf3 -c  -i 1 -t 10
> Output for iperf3:
> [  5]   0.00-1.24   sec  5.60 MBytes  37.7 Mbits/sec0   38.2 KBytes
>
> I'm facing issue of time interval with iperf3.
>
> On Mon, May 7, 2018 at 9:10 PM, Bob McMahon 
> wrote:
>
>> The client output for 2.0.10 with -e  and -i 1 could provide useful
>> information.
>>
>> Bob
>>
>> On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta 
>> wrote:
>>
>>> Hi Bob,
>>>
>>> Working without issue: iperf-2.0.10
>>> Time interval issue: iperf-3.3, iperf-3.1, iperf-3.5, iperf-3.0
>>>
>>> Regards,
>>> Nikita
>>>
>>> On Sat, May 5, 2018 at 3:37 AM, Bob McMahon 
>>> wrote:
>>>
 what version of iperf did you use?  iperf -v should provide that.

 If it's a later version of iperf2 the output on the client of with the
 -e option could be helpful.

 Bob

 On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta 
 wrote:

> Hi Bruce thanks for giving time on this issue.
>
> I am working on an embedded system with imx50.
> Server i'm using is RaspberryPi. Both the machines are connected on
> same network.
>
> Yes the system is a bit loaded. So this might be the reason.
> But if I reduce the window size then bandwidth also reduces and the
> time interval issue disappears.
>
> But with bandwidth of ~45M (which is the max it is showing) then it
> starts giving time interval issues.
>
> One more thing, I tried with iperf as well and its not giving any such
> issues on same machine with same server.
>
> On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:
>
>> If memory serves me right, Nikita Gupta wrote:
>> > Hi team,
>> >
>> > While checking network performance using iperf3, I'm facing interval
>> > issue at client end. Below are the logs:
>> >
>> > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
>> > KBytes
>> > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
>> > KBytes
>> > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
>> > KBytes
>> > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
>> > KBytes
>> > - - - - - - - - - - - - - - - - - - - - - - - - -
>> > [ ID] Interval   Transfer Bitrate Retr
>> > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec
>> 0 sender
>> > [  5]   0.00-10.12  sec   106 MBytes  87.6
>> Mbits/sec
>> > receiver
>> >
>> > I checked github bug #125 which was addressing this specific issue.
>> But
>> > no help.
>> > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all
>> versions,
>> > I'm getting the same issue.
>> >
>> > P.S. Server(with same iperf3 version) provides result as expected
>> with 1
>> > sec time interval, but client provides data at different time
>> intervals
>> > in every iteration.
>> > Kindly look into the issue and do let me know if m missing
>> something.
>>
>> What are the command line arguments you are using (both client and
>> server side, sanitize them as necessary0?  Also could you say
>> something
>> about the environment you're running in?  In particular, what OS and
>> hardware on the client and server, and what kind of network path are
>> you
>> going over?
>>
>> I rarely see issues like this (where the statistics printing intervals
>> are not aligned to whole second boundaries) in the middle of a test,
>> although it's been known to happen at the end of a test, for
>> conditions
>> that only happen at the end of a test.
>>
>> It seems like the timers within iperf3 that control when statistics
>> and
>> computed and printed aren't firing when they're supposed to.  On my
>> laptop (MacBook Pro) this happens close enough 

Re: [Iperf-users] iperf3: abrupt interval issue

[Nikita Gupta]

Yeah Bob,

Input command for iperf 2.0.10:
iperf -c  -e -i 1 -t 10
Output for iperf 2.0.10:
[  3] 0.00-1.00 sec  10.4 MBytes  87.0 Mbits/sec  83/0  0
42K/3464 us

input for iperf3:
iperf3 -c  -i 1 -t 10
Output for iperf3:
[  5]   0.00-1.24   sec  5.60 MBytes  37.7 Mbits/sec0   38.2 KBytes

I'm facing issue of time interval with iperf3.

On Mon, May 7, 2018 at 9:10 PM, Bob McMahon 
wrote:

> The client output for 2.0.10 with -e  and -i 1 could provide useful
> information.
>
> Bob
>
> On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta  wrote:
>
>> Hi Bob,
>>
>> Working without issue: iperf-2.0.10
>> Time interval issue: iperf-3.3, iperf-3.1, iperf-3.5, iperf-3.0
>>
>> Regards,
>> Nikita
>>
>> On Sat, May 5, 2018 at 3:37 AM, Bob McMahon 
>> wrote:
>>
>>> what version of iperf did you use?  iperf -v should provide that.
>>>
>>> If it's a later version of iperf2 the output on the client of with the
>>> -e option could be helpful.
>>>
>>> Bob
>>>
>>> On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta 
>>> wrote:
>>>
 Hi Bruce thanks for giving time on this issue.

 I am working on an embedded system with imx50.
 Server i'm using is RaspberryPi. Both the machines are connected on
 same network.

 Yes the system is a bit loaded. So this might be the reason.
 But if I reduce the window size then bandwidth also reduces and the
 time interval issue disappears.

 But with bandwidth of ~45M (which is the max it is showing) then it
 starts giving time interval issues.

 One more thing, I tried with iperf as well and its not giving any such
 issues on same machine with same server.

 On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:

> If memory serves me right, Nikita Gupta wrote:
> > Hi team,
> >
> > While checking network performance using iperf3, I'm facing interval
> > issue at client end. Below are the logs:
> >
> > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
> > KBytes
> > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
> > KBytes
> > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
> > KBytes
> > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
> > KBytes
> > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
> > KBytes
> > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
> > KBytes
> > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
> > KBytes
> > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
> > KBytes
> > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
> > KBytes
> > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
> > KBytes
> > - - - - - - - - - - - - - - - - - - - - - - - - -
> > [ ID] Interval   Transfer Bitrate Retr
> > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec
> 0 sender
> > [  5]   0.00-10.12  sec   106 MBytes  87.6 Mbits/sec
> > receiver
> >
> > I checked github bug #125 which was addressing this specific issue.
> But
> > no help.
> > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all
> versions,
> > I'm getting the same issue.
> >
> > P.S. Server(with same iperf3 version) provides result as expected
> with 1
> > sec time interval, but client provides data at different time
> intervals
> > in every iteration.
> > Kindly look into the issue and do let me know if m missing something.
>
> What are the command line arguments you are using (both client and
> server side, sanitize them as necessary0?  Also could you say something
> about the environment you're running in?  In particular, what OS and
> hardware on the client and server, and what kind of network path are
> you
> going over?
>
> I rarely see issues like this (where the statistics printing intervals
> are not aligned to whole second boundaries) in the middle of a test,
> although it's been known to happen at the end of a test, for conditions
> that only happen at the end of a test.
>
> It seems like the timers within iperf3 that control when statistics and
> computed and printed aren't firing when they're supposed to.  On my
> laptop (MacBook Pro) this happens close enough to the correct time that
> the timestamps appear to be exactly aligned to whole second boundaries
> (they're not, but close enough given the precision of printing the
> values in the output).  This situation could happen on slow hardware
> (some kind of embedded system?), on a virtual machine, or on a system
> that is very heavily loaded.  We would need some more information to
> determine which of this is 

Re: [Iperf-users] iperf3: abrupt interval issue

[Bob McMahon via Iperf-users]

The client output for 2.0.10 with -e  and -i 1 could provide useful
information.

Bob

On Mon, May 7, 2018 at 1:32 AM, Nikita Gupta  wrote:

> Hi Bob,
>
> Working without issue: iperf-2.0.10
> Time interval issue: iperf-3.3, iperf-3.1, iperf-3.5, iperf-3.0
>
> Regards,
> Nikita
>
> On Sat, May 5, 2018 at 3:37 AM, Bob McMahon 
> wrote:
>
>> what version of iperf did you use?  iperf -v should provide that.
>>
>> If it's a later version of iperf2 the output on the client of with the -e
>> option could be helpful.
>>
>> Bob
>>
>> On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta 
>> wrote:
>>
>>> Hi Bruce thanks for giving time on this issue.
>>>
>>> I am working on an embedded system with imx50.
>>> Server i'm using is RaspberryPi. Both the machines are connected on same
>>> network.
>>>
>>> Yes the system is a bit loaded. So this might be the reason.
>>> But if I reduce the window size then bandwidth also reduces and the time
>>> interval issue disappears.
>>>
>>> But with bandwidth of ~45M (which is the max it is showing) then it
>>> starts giving time interval issues.
>>>
>>> One more thing, I tried with iperf as well and its not giving any such
>>> issues on same machine with same server.
>>>
>>> On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:
>>>
 If memory serves me right, Nikita Gupta wrote:
 > Hi team,
 >
 > While checking network performance using iperf3, I'm facing interval
 > issue at client end. Below are the logs:
 >
 > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
 > KBytes
 > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
 > KBytes
 > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
 > KBytes
 > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
 > KBytes
 > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
 > KBytes
 > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
 > KBytes
 > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
 > KBytes
 > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
 > KBytes
 > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
 > KBytes
 > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
 > KBytes
 > - - - - - - - - - - - - - - - - - - - - - - - - -
 > [ ID] Interval   Transfer Bitrate Retr
 > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec0
 sender
 > [  5]   0.00-10.12  sec   106 MBytes  87.6 Mbits/sec
 > receiver
 >
 > I checked github bug #125 which was addressing this specific issue.
 But
 > no help.
 > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all
 versions,
 > I'm getting the same issue.
 >
 > P.S. Server(with same iperf3 version) provides result as expected
 with 1
 > sec time interval, but client provides data at different time
 intervals
 > in every iteration.
 > Kindly look into the issue and do let me know if m missing something.

 What are the command line arguments you are using (both client and
 server side, sanitize them as necessary0?  Also could you say something
 about the environment you're running in?  In particular, what OS and
 hardware on the client and server, and what kind of network path are you
 going over?

 I rarely see issues like this (where the statistics printing intervals
 are not aligned to whole second boundaries) in the middle of a test,
 although it's been known to happen at the end of a test, for conditions
 that only happen at the end of a test.

 It seems like the timers within iperf3 that control when statistics and
 computed and printed aren't firing when they're supposed to.  On my
 laptop (MacBook Pro) this happens close enough to the correct time that
 the timestamps appear to be exactly aligned to whole second boundaries
 (they're not, but close enough given the precision of printing the
 values in the output).  This situation could happen on slow hardware
 (some kind of embedded system?), on a virtual machine, or on a system
 that is very heavily loaded.  We would need some more information to
 determine which of this is the case (or whether it's something
 completely different).

 Bruce.





>>>
>>>
>>> --
>>> Regards,
>>> Nikita Gupta
>>>
>>> 
>>> --
>>> Check out the vibrant tech community on one of the world's most
>>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>>> ___
>>> Iperf-users mailing list
>>> Iperf-users@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/iperf-users
>>>
>>>

Re: [Iperf-users] iperf3: abrupt interval issue

[Nikita Gupta]

Hi Bob,

Working without issue: iperf-2.0.10
Time interval issue: iperf-3.3, iperf-3.1, iperf-3.5, iperf-3.0

Regards,
Nikita

On Sat, May 5, 2018 at 3:37 AM, Bob McMahon 
wrote:

> what version of iperf did you use?  iperf -v should provide that.
>
> If it's a later version of iperf2 the output on the client of with the -e
> option could be helpful.
>
> Bob
>
> On Thu, May 3, 2018 at 8:34 PM, Nikita Gupta  wrote:
>
>> Hi Bruce thanks for giving time on this issue.
>>
>> I am working on an embedded system with imx50.
>> Server i'm using is RaspberryPi. Both the machines are connected on same
>> network.
>>
>> Yes the system is a bit loaded. So this might be the reason.
>> But if I reduce the window size then bandwidth also reduces and the time
>> interval issue disappears.
>>
>> But with bandwidth of ~45M (which is the max it is showing) then it
>> starts giving time interval issues.
>>
>> One more thing, I tried with iperf as well and its not giving any such
>> issues on same machine with same server.
>>
>> On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:
>>
>>> If memory serves me right, Nikita Gupta wrote:
>>> > Hi team,
>>> >
>>> > While checking network performance using iperf3, I'm facing interval
>>> > issue at client end. Below are the logs:
>>> >
>>> > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
>>> > KBytes
>>> > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
>>> > KBytes
>>> > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
>>> > KBytes
>>> > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
>>> > KBytes
>>> > - - - - - - - - - - - - - - - - - - - - - - - - -
>>> > [ ID] Interval   Transfer Bitrate Retr
>>> > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec0
>>> sender
>>> > [  5]   0.00-10.12  sec   106 MBytes  87.6 Mbits/sec
>>> > receiver
>>> >
>>> > I checked github bug #125 which was addressing this specific issue. But
>>> > no help.
>>> > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all versions,
>>> > I'm getting the same issue.
>>> >
>>> > P.S. Server(with same iperf3 version) provides result as expected with
>>> 1
>>> > sec time interval, but client provides data at different time intervals
>>> > in every iteration.
>>> > Kindly look into the issue and do let me know if m missing something.
>>>
>>> What are the command line arguments you are using (both client and
>>> server side, sanitize them as necessary0?  Also could you say something
>>> about the environment you're running in?  In particular, what OS and
>>> hardware on the client and server, and what kind of network path are you
>>> going over?
>>>
>>> I rarely see issues like this (where the statistics printing intervals
>>> are not aligned to whole second boundaries) in the middle of a test,
>>> although it's been known to happen at the end of a test, for conditions
>>> that only happen at the end of a test.
>>>
>>> It seems like the timers within iperf3 that control when statistics and
>>> computed and printed aren't firing when they're supposed to.  On my
>>> laptop (MacBook Pro) this happens close enough to the correct time that
>>> the timestamps appear to be exactly aligned to whole second boundaries
>>> (they're not, but close enough given the precision of printing the
>>> values in the output).  This situation could happen on slow hardware
>>> (some kind of embedded system?), on a virtual machine, or on a system
>>> that is very heavily loaded.  We would need some more information to
>>> determine which of this is the case (or whether it's something
>>> completely different).
>>>
>>> Bruce.
>>>
>>>
>>>
>>>
>>>
>>
>>
>> --
>> Regards,
>> Nikita Gupta
>>
>> 
>> --
>> Check out the vibrant tech community on one of the world's most
>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>> ___
>> Iperf-users mailing list
>> Iperf-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/iperf-users
>>
>>
>


-- 
Regards,
Nikita Gupta
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot___
Iperf-users mailing list

Re: [Iperf-users] iperf3: abrupt interval issue

[Nikita Gupta]

Hi Bruce thanks for giving time on this issue.

I am working on an embedded system with imx50.
Server i'm using is RaspberryPi. Both the machines are connected on same
network.

Yes the system is a bit loaded. So this might be the reason.
But if I reduce the window size then bandwidth also reduces and the time
interval issue disappears.

But with bandwidth of ~45M (which is the max it is showing) then it starts
giving time interval issues.

One more thing, I tried with iperf as well and its not giving any such
issues on same machine with same server.

On Thu, May 3, 2018 at 11:49 PM, Bruce A. Mah  wrote:

> If memory serves me right, Nikita Gupta wrote:
> > Hi team,
> >
> > While checking network performance using iperf3, I'm facing interval
> > issue at client end. Below are the logs:
> >
> > [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
> > KBytes
> > [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
> > KBytes
> > [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
> > KBytes
> > [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
> > KBytes
> > [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
> > KBytes
> > [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
> > KBytes
> > [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
> > KBytes
> > [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
> > KBytes
> > [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
> > KBytes
> > [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
> > KBytes
> > - - - - - - - - - - - - - - - - - - - - - - - - -
> > [ ID] Interval   Transfer Bitrate Retr
> > [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec0
> sender
> > [  5]   0.00-10.12  sec   106 MBytes  87.6 Mbits/sec
> > receiver
> >
> > I checked github bug #125 which was addressing this specific issue. But
> > no help.
> > I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all versions,
> > I'm getting the same issue.
> >
> > P.S. Server(with same iperf3 version) provides result as expected with 1
> > sec time interval, but client provides data at different time intervals
> > in every iteration.
> > Kindly look into the issue and do let me know if m missing something.
>
> What are the command line arguments you are using (both client and
> server side, sanitize them as necessary0?  Also could you say something
> about the environment you're running in?  In particular, what OS and
> hardware on the client and server, and what kind of network path are you
> going over?
>
> I rarely see issues like this (where the statistics printing intervals
> are not aligned to whole second boundaries) in the middle of a test,
> although it's been known to happen at the end of a test, for conditions
> that only happen at the end of a test.
>
> It seems like the timers within iperf3 that control when statistics and
> computed and printed aren't firing when they're supposed to.  On my
> laptop (MacBook Pro) this happens close enough to the correct time that
> the timestamps appear to be exactly aligned to whole second boundaries
> (they're not, but close enough given the precision of printing the
> values in the output).  This situation could happen on slow hardware
> (some kind of embedded system?), on a virtual machine, or on a system
> that is very heavily loaded.  We would need some more information to
> determine which of this is the case (or whether it's something
> completely different).
>
> Bruce.
>
>
>
>
>


-- 
Regards,
Nikita Gupta
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot___
Iperf-users mailing list
Iperf-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/iperf-users

Re: [Iperf-users] iperf3: abrupt interval issue

[Bruce A. Mah]

If memory serves me right, Nikita Gupta wrote:
> Hi team,
> 
> While checking network performance using iperf3, I'm facing interval
> issue at client end. Below are the logs:
> 
> [  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec    0   42.4
> KBytes  
> [  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec    0   42.4
> KBytes  
> [  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec    0   42.4
> KBytes  
> [  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec    0   42.4
> KBytes  
> [  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec    0   42.4
> KBytes  
> [  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec    0   42.4
> KBytes  
> [  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec    0   42.4
> KBytes  
> [  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec    0   66.5
> KBytes  
> [  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec    0    112
> KBytes  
> [  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec    0    112
> KBytes  
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval   Transfer Bitrate Retr
> [  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec    0 sender
> [  5]   0.00-10.12  sec   106 MBytes  87.6 Mbits/sec 
> receiver
> 
> I checked github bug #125 which was addressing this specific issue. But
> no help.
> I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all versions,
> I'm getting the same issue.
> 
> P.S. Server(with same iperf3 version) provides result as expected with 1
> sec time interval, but client provides data at different time intervals
> in every iteration.
> Kindly look into the issue and do let me know if m missing something.

What are the command line arguments you are using (both client and
server side, sanitize them as necessary0?  Also could you say something
about the environment you're running in?  In particular, what OS and
hardware on the client and server, and what kind of network path are you
going over?

I rarely see issues like this (where the statistics printing intervals
are not aligned to whole second boundaries) in the middle of a test,
although it's been known to happen at the end of a test, for conditions
that only happen at the end of a test.

It seems like the timers within iperf3 that control when statistics and
computed and printed aren't firing when they're supposed to.  On my
laptop (MacBook Pro) this happens close enough to the correct time that
the timestamps appear to be exactly aligned to whole second boundaries
(they're not, but close enough given the precision of printing the
values in the output).  This situation could happen on slow hardware
(some kind of embedded system?), on a virtual machine, or on a system
that is very heavily loaded.  We would need some more information to
determine which of this is the case (or whether it's something
completely different).

Bruce.






signature.asc
Description: OpenPGP digital signature
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot___
Iperf-users mailing list
Iperf-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/iperf-users

[Iperf-users] iperf3: abrupt interval issue

[Nikita Gupta]

Hi team,

While checking network performance using iperf3, I'm facing interval issue
at client end. Below are the logs:

[  5]   0.00-1.05   sec  11.2 MBytes  88.7 Mbits/sec0   42.4
KBytes
[  5]   1.05-2.01   sec  10.0 MBytes  88.2 Mbits/sec0   42.4
KBytes
[  5]   2.01-3.07   sec  11.2 MBytes  88.4 Mbits/sec0   42.4
KBytes
[  5]   3.07-4.05   sec  10.3 MBytes  88.5 Mbits/sec0   42.4
KBytes
[  5]   4.05-5.11   sec  11.2 MBytes  88.6 Mbits/sec0   42.4
KBytes
[  5]   5.11-6.06   sec  10.0 MBytes  88.7 Mbits/sec0   42.4
KBytes
[  5]   6.06-7.07   sec  10.7 MBytes  89.0 Mbits/sec0   42.4
KBytes
[  5]   7.07-8.02   sec  10.0 MBytes  88.6 Mbits/sec0   66.5
KBytes
[  5]   8.02-9.09   sec  11.1 MBytes  86.8 Mbits/sec0112
KBytes
[  5]   9.09-10.06  sec  10.0 MBytes  85.7 Mbits/sec0112
KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval   Transfer Bitrate Retr
[  5]   0.00-10.06  sec   106 MBytes  88.1 Mbits/sec0 sender
[  5]   0.00-10.12  sec   106 MBytes  87.6 Mbits/sec
receiver

I checked github bug #125 which was addressing this specific issue. But no
help.
I have tried iperf3.0.5, iperf3.1, iperf3.3, iperf3.5. In all versions, I'm
getting the same issue.

P.S. Server(with same iperf3 version) provides result as expected with 1
sec time interval, but client provides data at different time intervals in
every iteration.
Kindly look into the issue and do let me know if m missing something.

-- 
Regards,
Nikita Gupta
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot___
Iperf-users mailing list
Iperf-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/iperf-users