Comments (3)
Yes batch timestamping is intended behaviour. Changing this a bit, by putting a
timestamp in individual buffers as packets are processed (which does not
correspond to the actual reception) would have some significant loss of
performance at high rates, and no real advantage. Note that the software
timestamping done in the network stack does not reflect arrival times either:
even without netmap you get an interrupt from the NIC with a one or more
packets, then the napi/softintr thread starts timestamping packets as it
processes them.
The "out of order" packets (I assume you refer to packets from different
queues) phenomenon could be observed also with the standard drivers.
On passing: the D(), RD() and ND() macros are generic debugging helper not
related to
packet timestamps.
Original comment by [email protected]
on 30 Sep 2014 at 7:41
- Changed state: Invalid
- Added labels: Priority-low, type-other
- Removed labels: Priority-Medium, Type-Defect
from netmap.
Hi Rizzo:
Thank you for your quick response. What I meant by "out of order" purely from a
post processing stand point. We are using netmap as a pcap logger. But post
processing tools such as wireshark attempts to index packets based on
timestamp, multiple packets sharing the same time timestamp would not get
presented in accurate order in wireshark. I understand the lack of accuracy of
software timestamping overall. Just out of curiousity, what is performance
penalty of having timestamp on individual buffers? I understand much
improvement has been put into netmap, is it still be faster than standard
networking stack?
Original comment by [email protected]
on 30 Sep 2014 at 8:29
from netmap.
The reordering is a bug in whatever presentation tool you are using. It should
use a stable sort algorithm.
With a microsecond timestamp resolution there is no way netmap or any other
capture library can guarantee that all packets have different timestamps (they
can be 67ns apart on the wire).
Original comment by [email protected]
on 1 Oct 2014 at 10:16
from netmap.
Related Issues (20)
- Running multiple pkt-gen applications for receiving packets HOT 1
- OpenWRT Makefile does not work
- [PATCH] Allow use of pipes in pkt-gen through "-E" HOT 2
- Is it possible to make netmap kernel version agnostic HOT 2
- Run Netmap in a Fedora VM running in VirtualBox HOT 2
- Netmap on CentOS 7 work abnormally HOT 1
- No packets received no the receiver side in the simple pkt-gen example HOT 1
- Something wrong with Netmap bridge HOT 2
- netmap crash on ubuntu 14.04 after weeks of continuous use
- running netmap-libpcap linked tcpdump slows pkt-gen and drops packets
- Problems installing Netmap on ARM (Nvidia Jetson TK1) HOT 4
- Conflict with Boost Threads, patch provided
- Can't build ixgbe driver for Debian 7 Wheezy HOT 3
- Kernel oops when trying to open netmap with incrorrect hardware RING number HOT 2
- Debian 7.8, e1000e plus netmap build error HOT 2
- get in touch HOT 4
- examples/bridge connect to host stack on e1000 only see net->host,no host->net HOT 2
- Intel ixgbe driver from Sourcesorge
- Optimization on linux - hugetlb pages support HOT 3
- Kernel panic with Fedora 21 (Linux 3.19 kernel) and e1000 driver
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