On Wednesday, August 20, 2014 1:08:17 AM UTC+8, Kushal Kumaran wrote:
> On Tue, Aug 19, 2014 at 1:09 PM, yuzhichang <[email protected]> wrote:
>
> > Hi all,
>
> > I'm new to asyncio introduced by Python 3.4. I created two tasks each
> > pings a host. I noticed some pieces of output will be lost(see "error:
> > found icmp_seq gap"). If I changed to run only one task, this problem never
> > occur.
>
> > Do you have any idea?
>
> > Thanks!
>
> > Zhichang
>
> >
>
> > zhichyu@cto-team-6:~$ python3 asyn2.py
>
> > got line: b'PING tyr.global.tektronix.net (10.250.163.252) 56(84) bytes of
> > data.\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=2 ttl=55 time=204 ms\n'
>
> > got line: b'PING babylon.rich.tek.com (10.250.155.123) 56(84) bytes of
> > data.\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=2
> > ttl=55 time=205 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=3
> > ttl=55 time=205 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=3 ttl=55 time=205 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=4
> > ttl=55 time=196 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=4 ttl=55 time=198 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=5 ttl=55 time=181 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=5
> > ttl=55 time=182 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=6
> > ttl=55 time=180 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=6 ttl=55 time=179 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=7
> > ttl=55 time=193 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=7 ttl=55 time=196 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=8 ttl=55 time=185 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=8
> > ttl=55 time=187 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123): icmp_seq=9
> > ttl=55 time=213 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=9 ttl=55 time=211 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123):
> > icmp_seq=10 ttl=55 time=192 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=10 ttl=55 time=192 ms\n'
>
> > got line: b'64 bytes from tyr.global.tektronix.net (10.250.163.252):
> > icmp_seq=11 ttl=55 time=210 ms\n'
>
> > got line: b'64 bytes from babylon.rich.tek.com (10.250.155.123):
> > icmp_seq=12 ttl=55 time=210 ms\n'
>
> > error: found icmp_seq gap!
>
> >
>
> > <snipped code>
>
>
>
> Before looking for possible bugs in your code, the first thing to
>
> check would be if you are actually missing ping replies, rather than
>
> output from the ping command. Try increasing the timeout (-W) for the
>
> ping command. If you're familiar with tools like tcpdump and
>
> wireshark, you could use those to examine the network traffic and see
>
> if replies are missing.
>
>
>
> --
>
> regards,
>
> kushal
Hi kushal,
Wireshark shows some replies are missing. Changing destinations to
localhost in code also fix the "icmp_seq gap" error. I should be more careful
on debug these things.
Thanks for your help!
Zhichang
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