Jon, Marc:
thank you for information! I modified following kernel parameters:
#UDP socket receive buffer
net.ipv4.udp_rmem_min
#UDP socket send buffer
net.ipv4.udp_wmem_min
#TCP socket receive max buffer size
net.core.rmem_max
#TCP socket send max buffer size
net.core.wmem_max
..under Debian
it is used for dimensioning the *buffer*. It is not
> very clear to me.
It helps a little if you read the code (see src/iperf_tcp.c), but
basically what's happening is that the option sets the sender and
receiver socket buffer sizes. These have the side effect of setting the
TCP window size.
For
, but
> basically what's happening is that the option sets the sender and
> receiver socket buffer sizes. These have the side effect of setting the
> TCP window size.
>
> For UDP, there's no window size of course. But it's still useful to set
> the socket buffer si
Excerpts from Martin T's message of Wed Apr 06 18:43:12 -0500 2011:
> Jon, Marc:
>
> thank you for information! I modified following kernel parameters:
>
> #UDP socket receive buffer
> net.ipv4.udp_rmem_min
> #UDP socket send buffer
> net.ipv4.udp_wmem_min
> #TC
45:08 HNDLR_ udp-rx Receiving 1470 byte datagrams (sflx2,file12)
20:45:08 HNDLR_ udp-rx UDP buffer size: 8388608 Byte (WARNING: requested
735 Byte) (sflx2,file12)
20:45:08 LOG itx-lx1iperf -c 192.168.1.42 -w 367500 -l 1470 -u -b 2G -B
192.168.1.100 -i 0.1 -fb -S 0x0 -T 25
g properly and responding as expected when RF
>> > attenuation is added and then removed.
>> >
>> > utf> udp start; udp linkcheck -now; L1 attn 65; UTF::Sleep 0.3; L1
>> > attn
>> 0;
>> > UTF::Sleep 0.3; udp stop
>> > 20:45:08 LOG sfa
Hi Thomi,
2009/4/15 Thomi Schmid :
> According to iperf's doc:
> -w, --window #[KM] ... For UDP it is just the buffer which datagrams are
> received in, and so limits the largest receivable datagram size.
The -w option is just passed to the kernel as SO_SNDBUF (resp.
SO_RCVBU
orever if there is a problem. In short, it adds an additional minute
to the time the test is run for and kills the process if it exceeds
that time.
What appears to be happening is that when doing UDP testing
(dualtest), the final packets do not always make it to the server, so
the server leaves the sock
when) I'm
> wrong:
>
> (1) The -w switch really isn't the TCP Receive Window as the
> documentation says but rather the send/receive socket buffer size, and
> is not directly related to TCP Window Size. This goes against what I had
> originally assumed from the documentation
i 0.1 -fb -p
> 60001
> 20:45:08 HNDLR_ udp-rx Server listening on UDP port 60001
> (sflx2,file12)
> 20:45:08 HNDLR_ udp-rx Receiving 1470 byte datagrams (sflx2,file12)
> 20:45:08 HNDLR_ udp-rx UDP buffer size: 8388608 Byte (WARNING:
> requested 735 Byte) (sflx2,file12)
>
-now; L1 attn 65; UTF::Sleep 0.3; L1 attn
> 0;
> > UTF::Sleep 0.3; udp stop
> > 20:45:08 LOG sfast-lx2 iperf -s -w 735 -l 1470 -u -i 0.1 -fb -p
> > 60001
> > 20:45:08 HNDLR_ udp-rx Server listening on UDP port 60001
> > (sflx2,file12)
> > 20:45:08
There is no way to know. UDP is lossy, after all.
On Wed, Sep 17, 2014 at 7:47 AM, Martin T wrote:
> Andrew,
>
> if Iperf ignores the errors regarding lack of memory in interface
> buffers, then how does Iperf know that it should send out the
> datagrams less frequently, i.e.
t; which I use for wi-fi testing. The following shows an 802.11 AC
>> wi-fi
>> >> link
>> >> > that maxes out around 800Mbs. The offered load is 2G and the iperf
>> >> client
>> >> > seems to be reporting properly and responding as expect
;>> >> > sure why that's interesting.
>>> >> >
>>> >> > As an FYI, I have a tool that manages multiple, distributed iperf
>>> >> sessions
>>> >> > which I use for wi-fi testing. The following shows an 802.11 AC
>&
=ENOBUFFS
> >>> >> before
> >>> >> > the ReportPacket()
> >>> >> >
> >>> >> > Also, ione could count the number of writes that return ENOBUFFS
> >>> >> > but
> >>> >> > not
> >>>
dicating the number of bytes
> written into kernel space) or a (negative value indicating some sort of
> socket write error.) The iperf client will terminate on all socket write
> errors except ENOBUF (which it silently ignores.) The write will preserve
> the UDP payload, i.e
Hi Martin,
>
> Yes, the value is either a positive integer (indicating the number of bytes
> written into kernel space) or a (negative value indicating some sort of
> socket write error.) The iperf client will terminate on all socket write
> errors except ENOBUF (which it silently ig
udp stop
> 20:45:08 LOG sfast-lx2 iperf -s -w 735 -l 1470 -u -i 0.1 -fb -p
> 60001
> 20:45:08 HNDLR_ udp-rx Server listening on UDP port 60001
> (sflx2,file12)
> 20:45:08 HNDLR_ udp-rx Receiving 1470 byte datagrams (sflx2,file12)
> 20:45:08 HNDLR_ udp-r
>> >>> >> > A minor nit, the currLen may need to set to zero when
>> >>> >> > errno==ENOBUFFS
>> >>> >> before
>> >>> >> > the ReportPacket()
>> >>> >> >
>> >>> >>
r of write() per seconds.
> There is a "physical" limit caused by either the CPU, or memory bandwidth,
> or scheduling, etc. What is the maximum UDP sending rate you ever saw
> reported on this specific hardware and operating system?
>
> As already suggested on this lis
kDefault_UDPBufLen;
with const int kDefault_UDPBufLen = 1470
For the first one it could be that a bug entry already exists
in a tracker.
2. recv is used with a buffer of that size, which is too small to
take UDP packets in general (they can be up to almost 64KB),
see man recv:
; >> > // report packets
>> >>> >> > reportstruct->packetLen = currLen;
>> >>> >> > ReportPacket( mSettings->reporthdr, reportstruct );
>> >>> >> >
>> >>> >> > A minor nit, the currLen may need
ote:
>>> 2) Iperf client didn't send the data at faster rate than 120Mbps
>>> because it received some error-signals from kernel and immediately
>>> sent out datagrams less frequently
>>
>> Whether packets are lost inside the sender or not and no matter how
and no matter how hard it
> tries, the client cannot perform an infinite number of write() per seconds.
> There is a "physical" limit caused by either the CPU, or memory bandwidth,
> or scheduling, etc. What is the maximum UDP sending rate you ever saw
> reported on thi
ived some error-signals from kernel and immediately
>>> sent out datagrams less frequently
>>
>> Whether packets are lost inside the sender or not and no matter how hard it
>> tries, the client cannot perform an infinite number of write() per seconds.
>> There is a &
, changing the socket buffer size
to be smaller/bigger than some tx_ring would trigger packet drops
inside the kernel. Probably not very useful, but making iperf actually
"send&quo
2010/2/22 Yousuf Ahmad :
> How does iperf use “b, w and l” parameters?
AFAIK Iperf does nothing with the socket buffer size argument ('-w')
but pass it to your operating system.
> Is there a way I can calculate or estimate their value in order to achieve
> max. UDP throughp
mped fro 40MBit/s to 70 MBit/s for dual mode; and from 70MBit/s to
90Mbit/s for single mode. So at least the UDP perfomance looks like the TCP
performance I get out of this hardware.
Regs,
Thomi
Am Dienstag, 14. April 2009 01.41:40 schrieben Sie:
> Hi,
>
> Try different values for the s
need to ensure you have the
driver's queue
large enough (or the socket buffer small enough) so that the driver's queue can
hold an
entire socket buffer worth of traffic (* the number of active sockets per
queue). You can change
the driver's queue size via ifconfig txqueuelen. It mig
ive the same results. I compiled a newer
> version of Iperf for use with Windows which “behaved” better, but only after
> adjusting the –w settings.
The socket buffer size has an impact on how some kernels drop UDP
packets. You will find more information about this in the ar
f use “b, w and l” parameters?
>
> AFAIK Iperf does nothing with the socket buffer size argument ('-w')
> but pass it to your operating system.
>
>
> > Is there a way I can calculate or estimate their value in order to achieve
> > max. UDP throughput for a given
d on iperf but on the operating system.
For both UDP and TCP what the sending side reports is what has been
sent, NOT what has been received. So it can differ between the sending
and receiving side. But for TCP it cannot differ for long, because in
case of a network problem the TCP socket buffer o
opping
> packets when the device's
>
> queue is full *AND* when the device queue is too small to hold the entire
> socket buffer's worth
>
> of traffic. If you want blocking behavior, you need to ensure you have
> the driver's queue
>
> large enough (or
I can never get the final results such as loss, pings etc.
>
> ---
>
> root# iperf -c domain.com -p 2131 -u -b 1m -t 5 -i 1 -f m
> --------
> Client connecting to domain.com, UDP port 2
d
>>
>> not be accepted into the kernel.
>>
>>
>>
>> What is really happening is that the linux kernel is silently dropping
>> packets when the device's
>>
>> queue is full *AND* when the device queue is too small to hold the entire
>&g
ceforge.net/mailarchive/message.php?msg_name=4695C66E.5020205
%40room52.net
This is my understanding so far, please correct me if (read: when) I'm
wrong:
(1) The -w switch really isn't the TCP Receive Window as the
documentation says but rather the send/receive socket buffer size, and
is
ending
> and receiving side. But for TCP it cannot differ for long, because in
> case of a network problem the TCP socket buffer on the sending side
> will fill up and eventually block the sender.
Do I understand it right that iperf on the client site doesn't calculate the
true bandwidth?
for use with Windows which "behaved" better, but only after
> adjusting the -w settings.
The socket buffer size has an impact on how some kernels drop UDP
packets. You will find more information about
After a couple days of digging on the problem, I've found out (through my
own watered down implementation of a iperf-like tool) that the sendto method
is blocking at higher rates (indicating the buffer is full). I verified
this by chaning my implementation to be non blocking on that socket
nel is silently dropping
packets when the device's
queue is full *AND* when the device queue is too small to hold the entire
socket buffer's worth
of traffic. If you want blocking behavior, you need to ensure you have the
driver's queue
large enough (or the socket buffer small enough)
silently returns NETDEV_TX_OK & does not stop its txqueue, but a
>> driver
>> that broken would
>>
>> not be accepted into the kernel.
>>
>>
>>
>> What is really happening is that the linux kernel is silently dropping
>> packets when the devic
Just a heads up that we just released iperf 2.0.10 on sourceforge
<https://sourceforge.net/projects/iperf2/>.
Change set includes:
o Clean up help and man page for -V option
o UDP IPv6: Default the mBuf size to 1450 for the client, default the
Listener/server to 1470
o Display read/write
( report_bw_format, stats->transferID,
stats->startTime, stats->endTime,
buffer, &buffer[sizeof(buffer)/2] );
} else {
// UDP Reporting
if( !header_printed ) {
-printf( report_bw_jitter_loss_header);
+p
> wrote:
> >
> >> Hi Drew,
> >>
> >>
> >>
> >> Thanks for the detailed explanation. Do you know any reason that iperf
> >> doesn’t or shouldn’t set IP_RECVERR on the sending socket(s)?
> >>
> >>
> >
That's how iperf works as is with -u UDP. The -b bandwidth setting
combined with the -l payload length settings are used to calculate the
interpacket gap or delay. The period is defined by this computed
interpacket delay.Note that iperf is an application so the period sets
the s
,
- int isipv6);
-
-/*Sets the socket option so that we can read ancillary data from UDP packets*/
-int
-enable_ancillary_data (int sock, int isipv6);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /*UDPMESSAGE_H_*/
diff -Naur iperf-2.0.4/src/Listener.cpp temp/iperf-2.0.4/src/Listener.cpp
--- iperf-2.0.4/s
the sending
and receiving side. But for TCP it cannot differ for long, because in
case of a network problem the TCP socket buffer on the sending side
will fill up and eventually block the sender.
Do I understand it right that iperf on the client site doesn't calculate the
true band
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA512
ESnet (Energy Sciences Network) proudly announces the public release
of iperf-3.0.10. This release includes several fixes, including a
build fix for MacOS X Yosemite and a fix for the -w (socket buffer
size) option for UDP tests.
More information
d. It may require a control socket similar to iperf 3.
We've purposely tried to avoid a TCP socket for UDP tests in iperf 2 so
it's not something we'd want to do.
The question becomes, should this all be a python script using flows or is
there enough value add in having iperf do it it
I
> doubt this will work for your triangulation needs.) Using a python script,
> one can then just use iperf and add the new features via python code.
>
> Note: Adding step sync over UDP with iperf isn't trivial - too much
> handshaking required. It may require a control socket
With such high levels of oversubscription you might want to increase the
socket buffer sizes (using -w) This will allow the network stack to accept
the application level write() and "drop" them even if the wl driver and
link is saturated. If the window size is too small the applica
ized before each step or for
>> triangulated flows (iperf 2.0.14 does support --incr-dstip with -P but I
>> doubt this will work for your triangulation needs.) Using a python script,
>> one can then just use iperf and add the new features via python code.
>>
>> Note: Add
ip-times might be useful too. Man
>>> page here <https://iperf2.sourceforge.io/iperf-manpage.html>
>>>
>>> I'd suggest writing a python script using pyflows
>>> <https://sourceforge.net/p/iperf2/code/ci/master/tree/flows/> if you
>>>
the to/fro directions as well as full duplex (as
>>>> well as set the access class to VOIP priority.)
>>>>
>>>> If you can get clock sync then --trip-times might be useful too. Man
>>>> page here <https://iperf2.sourceforge.io/iperf-manpage.html&
c then --trip-times might be useful too. Man page
> here
>
> I'd suggest writing a python script using pyflows if you need the full duplex
> case to be synchronized before each step or for triangulated flows (iperf
> 2.0.14 does support --incr-dstip with -P but I doubt t
-range=1m,10m,1m
>>>>>--sweep-step 10 -i 1 -l 200 -S 0xc0
>>>>>- iperf -c --u --sweep-range=1m,10m,1m
>>>>> --sweep-step 10 -i 1 -l 200 -S 0xc0
>>>>>
>>>>> which should cover the to/fro directions as well as full
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA512
ESnet (Energy Sciences Network) announces iperf-3.1.3, the latest
point/bugfix release from the iperf 3.1 codeline.
iperf-3.1.3 fixes an important security issue in all previous versions
of iperf3. That issue was a buffer overflow / heap
n get clock sync then --trip-times might be useful too. Man
> page here
> >
> > I'd suggest writing a python script using pyflows if you need the full
> duplex case to be synchronized before each step or for triangulated flows
> (iperf 2.0.14 does support --incr-dstip with -P
case to be synchronized before each step or for triangulated flows
(iperf 2.0.14 does support --incr-dstip with -P but I doubt this will work for
your triangulation needs.) Using a python script, one can then just use iperf
and add the new features via python code.
>
> Note: Adding ste
erse -u --sweep-range=1m,10m,1m
>> --sweep-step 10 -i 1 -l 200 -S 0xc0
>> > • iperf -c --u --sweep-range=1m,10m,1m
>> --sweep-step 10 -i 1 -l 200 -S 0xc0
>> > which should cover the to/fro directions as well as full duplex (as
>> well as set the access clas
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