1
vote
2answers
273 views

Low latency TCP settings on Ubuntu

There is a server for measurements running on Ubuntu in my lab . And there is C program, which receives data through TCP connection and should as soon as possible send a reply. Network latency when ...
-2
votes
1answer
30 views

Users unable to connect due to an unknown plausible reason [closed]

========================= Warning: Long thread; includes a lot of information to give you some basic understanding of my issues. If you rather not read it, then here are my questions: 1) Does Linux ...
1
vote
1answer
76 views

Network ping replies: latency alternates low and high

I'm experiencing some troubles with one machine in my network. When I ping it the ping replies rotates like this : 64 bytes from 10.0.100.10: icmp_seq=156 ttl=62 time=100 ms 64 bytes from ...
0
votes
2answers
132 views

Apache has a long lag before responding

I have an Apache server on CentOS that occasionally takes 1-5 seconds to serve a file, including a text file that is 2 characters. I have a JMeter test that gets a few different types of files, and ...
-1
votes
1answer
44 views

Dedicating a server for latency test

I've created a server to test bandwidth from employees working remote (using speedtest.net mini), but was wondering if anyone knew of a way to setup some software in linux to test latency and possibly ...
0
votes
0answers
205 views

CentOS Latency High Troubleshooting

I have two CentOS servers connected via a 10 Gb fiber optic cable with a network emulator connected between them. All three units sit on a desk in the lab. There is also a regular 1 Gbit Ethernet ...
1
vote
0answers
259 views

how to disable MSI on tg3 driver?

got some new HP DL380p G8 for Centos. What's the correct options to disable MSI for the onboard Broadcom NICs? I tried disable_msi in modprobe.conf.local and it doesn't work. Thanks Will
6
votes
1answer
2k views

Limit incoming and outgoing bandwidth and latency in linux

I realise many similar questions have already been asked, but so far I've yet to find a solution to my problem. I have a virtual linux server (running Debian Squeeze) that I use for testing of ...
-1
votes
1answer
317 views

Ultra Low Latency Linux Distribution or Kernel [closed]

I'd like to know if there are any linux distributions that are focused on low latency networking. The area I'm working in is algorithmic trading, and extremely low latency comms between machines is a ...
0
votes
2answers
97 views

Impact of Traffic through the first NIC on the second NIC

I have two NICs on a RHEL 6 server. They are both set at 1GB/sec full duplex. The first NIC has lots of small (< 100 byte) TCP socket writes. The second NIC is used to receive a 50 MB/sec TCP input ...
3
votes
2answers
866 views

LatencyTop on Centos 6.2

What do I need to do to get LatencyTop working on Centos 6.2? Does it involve compiling a debug kernel with some extra flags? Both the man page and the website are very short of information. ...
4
votes
2answers
151 views

OS parameters tuning for latency improvement

We are trying to improve the average latency of Java proxy application. The Java application receives a message from a client and proxies it to a necessary server. The protocol is binary, ...
0
votes
1answer
118 views

What settings should I modify to tune a Linux server for very small yet very high packet rate UDP receive loads?

I am tuning a server that needs to handle small (average of about 50 bytes) UDP packets. The average packet rate is approximately 100,000 packets/second. The data is very burst and can sometimes burst ...
1
vote
1answer
282 views

ping6 overhead compared to ping overhead

I am testing IPv6 latency from a Linux box, and I noticed this weird difference between IPv4 ping and IPv6 ping: # ping -n -A -q -c 500 speedtest.steffann.nl PING speedtest.steffann.nl (10.3.10.20) ...
4
votes
7answers
5k views

Latency in TCP/IP-over-Ethernet networks

What resources (books, Web pages etc) would you recommend that: explain the causes of latency in TCP/IP-over-Ethernet networks; mention tools for looking out for things that cause latency (e.g. ...
1
vote
2answers
1k views

use of tcp_delack_min on redhat linux (kernel 2.6.18)

we're moving from Solaris to Redhat Linux, and trying to duplicate our low-latency setup, that, on solaris, includes the ndd settings related to TCP NO DELAY, and NAGLE ALGORITHM. I got the impression ...
3
votes
1answer
372 views

Can Linux RAID 1 account for high latency?

Scenario: we're running a large (3TB total in cluster) Solr installation in EC2. I'm only concerned about disk performance on the read side of things. We suspect that we are limited by disk I/O and ...
7
votes
5answers
9k views

Tuning NFS for minimum latency

How can I achieve low latency for NFS exports in order to e.g. have developers work nicely in Eclipse/Visual Studio with their workspaces mounted over NFS?