Is there a way to obtain CPS and Thruoghput metrics in Linux?
Jul 25
I want to analyze my Debian 9 server's network workload to detect some possible network overloads.
The main metrics I need to analyze are:
- CPS (connections per second)
- Throughput
Is there a way to obtain these metrics from within Linux?
I thought that CPS metric could be somehow obtained through conntrack NEW connections events but not sure that this would be the most proper way..
Sorry if obvious.
P.S. this server handles not only local traffic, it also forward a lot of traffic.
linux1 answer
Accepted answer · original discussion
Aug 2
I think it would be sufficient to describe these metrics' origins based on native Linux API.
Throughput
By the way, the throughput metric in general is something, that is external in relation to the testing object (OS Linux you're talking about). I.e. roughly speaking we have two hosts (e.g. client and server) and testing object between them. We blow the network traffic between client and server and record the (boundary) throughput of testing object (e.g. with iperf).
But from within OS Linux a simple way we can measure throughput is only per interface.
So you can just watch /proc/net/dev and calculate the delta of bytes per second:
sh-tst# cat /proc/net/dev
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
lo: 87016202 715723 0 0 0 0 0 0 87016202 715723 0 0 0 0 0 0
eth3: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
eth2: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
eth1: 246415305 2899662 0 132906 0 0 0 230 5466117 19016 0 0 0 0 0 0
eth0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
CPS
The same thing is for CPS metric. Basically it is an external measurement.
But from within your Linux you can try to calculate it based on the /proc/net/stat/ip_conntrack:
sh-tst# cat /proc/net/stat/ip_conntrack
entries searched found new invalid ignore delete delete_list insert insert_failed drop early_drop icmp_error expect_new expect_create expect_delete search_restart
000000f8 00001742 0003142f 0001e85a 00000079 00021333 0001e6cf 00003a3d 00003bc5 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
000000f8 00002389 0005f1a0 0003b6f3 00000085 0004286f 0003b59e 00003cea 00003e3f 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
000000f8 000002c0 00037a77 00000714 00000000 000382cb 00000825 00000724 00000616 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
000000f8 00000225 00026cf9 00000271 00000000 00026e48 00000348 000002bd 000001e6 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
From lnstat(8) man:
/proc/net/stat/ip_conntrack, /proc/net/stat/nf_conntrack Conntrack related counters. ip_conntrack is for backwards compatibility with older userspace only and shows the same data as nf_conntrack.
...
new Number of conntrack entries added which were not expected before.
In Linux connection tracking:
NEW -- meaning that the packet has started a new connection, or otherwise associated with a connection which has not seen packets in both directions, and
So seems that you want to calculate delta new per second.
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Jul 25