I have a four-cores machine (core1,core2, core3, core4 ). I want to test the communication or latency between two cores (for example, core1 and core2; core3 and core4). Does anyone know how to write a code to test it under linux operating system?
View 1 RepliesHow do I find out the memory bandwidth/latency to RAM of the machine?
View 3 Replies View RelatedI have created mobility of 20 nodes and vbr traffic using following attached script I executed the file as ns234 vbr.tcl I got the vbr.tr and vbr.nam but I was unable to load the graph using matlab <trgraph> I thought problem with is vbr.tcl script.
View 1 Replies View RelatedInterpreting the output of /etc/proc/cpuinfo.
This is a Linux Box.
Here is the output and I need to know how many CPUs we have and how many cores per CPU.
Program code as how to measure interrupt latency..
View 2 Replies View RelatedWhen I was using Virtual Box in Windows 7, I could choose how many CPU cores to assign to the guest OS. Now I'm using Linux, and when I installed Virtual Box, I couldn't find that option. System Monitor shows that when the VM is busy only one CPU core goes to 100% while the rest are near 0%. How can I make Virtual Box in Linux use multiple CPU cores?
View 2 Replies View RelatedI am using the standalone k10temp temperature sensor but it doesn't give the actual temperature of the cpu, just some "bogus" temp value that isn't very useful.Does anyone know how you can calculate the real temperature from this reading?
View 3 Replies View RelatedI'm looking for an open source/free network emulator tool that I could use on Mac OS X, to simulate a slow network connection, limited bandwidth and other network characteristics such as dropped packets etc for both UDP/TCP connections (or even on the physical layer).
I'm looking for the simplest solution that would allow me to run TCP/UDP servers and have a few clients connect to them on localhost emulating various network connections. I'm mainly wondering if I can use something like Linux's netem on Mac OS X (or even better cross-platform Windows/Linux/Mac). Perhaps I can run VirtualBox and a Linux kernel running netem, has anyone had luck with that?[URL]...
I'm hoping to find an existing Linux tool for measuring latency:
I'm trying to diagnose how much latency my OS and NIC card are adding to TCP latency in Linux. I looked at the following tools but all (at least at the surface level) measured bandwidth (Mbps/sec) rather than latency (nanoseconds for transmition of 1 packet of size x).
If I were to write a custom test, it would likely do the following:
Client:
Create a fake message of the specified length with some padding for an incrementing identifier. Open a TCP connection (with the right parameters like TCP_NODELAY, etc) Loop and send messages containing an incrementing identifier. Store the current system time (in nanos) associated with the identifier. Listen for responses, record the current time and record the latency of that identifier asynchronously Server Listen for a connection Echo back any message received
Assuming both boxes had the same setup (configs, cards, OS, CPU, etc), are relatively close to eachother in the network, and one knows roughly the network's latency contribution, one could get a rough estimate of the OS + NIC contribution and begin testing various configurations.
One could also get a more accurate picture of the latency by using a network sniffer and snooping on the lines between the two hosts, calculating the latency between the two sides for an ID, and then subtracting that from the internally measured latency.
i have installed ns 2.33 and added the patch mobiwan for supprting mobile ipv6. i ran some tcl scripts , and below is the trace file generated. calculate the handoff latency, and if someone has awk or perl script to do so, tcl file [URL] out.tr [URL]
View 1 Replies View RelatedMany commands in Mathematica 8 (Integrate, Simplify, etc.) seem to only be using a single core on my system. Is there any way I can change the affinity so that it utilizes all cores for computations?
View 3 Replies View RelatedI have a 8 core computer, which has 8 logical processor in total. I want to create 8 process(nodes). Each node is mapped to each logical processor. The order is code...
I wrote the code as below, could you please see whether it is correct? code...
I am new to the forum and new to Linux.
I am trying to explore if Linux can be run on a multicore platform when the max frequency of one the cores is less than the others.
please give me some pointers or let me know if you have tried such HW configuration.
There is a computer with two "Xeon(R) CPU X5550 @ 2.67GHz" CPU. The Hyper-threading is enabled, so it looks like 16-core system, but really there is only 8 physical cores.
I know that when hyperthreading is enabled, each physical core is splitted into two virtual cores. I want to know, which pair of virtual cores shares a physical core and which are not. Or, how (in what order) will Linux enumerate HT-cores comparing to real cores. (enumerating is done for sched_setaffinity and taskset masks).
I have a dump of /proc/cpuinfo file from the system.
I think there are possible:
CPU0-CPU7 are not sharing phys. core. CPU8-CPU15 too. But sharing is in pairs CPU0+CPU8, CPU(i)+CPU(i+8) and so on. or CPU0+CPU1 are from single physical, CPU2+CPU3, CPU(2*i)+CPU(2*i+1). or exotic CPU0+CPU15 sharing, CPU1+CPU14 ... or random?
The hard moment in this case is that there are 2 physical dies of CPU (two sockets), and usual recommendation of using "physical id:" field can't help
The cpuinfo:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU X5550 @ 2.67GHz
[Code].....
I have installed Postfix + Amavisd-new, then I am started all services (and configured main.cf and master.cf to use amavis).
The questions are:
1) I am trying to test antivirus scan using eicar test virus
Code:
And the message is successfully delivered to mailbox with mark "CLEAN" in maillog. But I cant see any attachment using
Code:
Where is my mistake?
2) Should I update clam and how I can do it?
3) Is spamassassin enabled by default in amavis (I have started daemon)?
4) Where configuration files of spamassassin is stored?
I am trying to install mysql 5.1.44..so i downloaded the binary package, i extracted it and then followed the instructions that were in the manual but i keep getting this error when running this command
Code:
scripts/mysql_install_db --basedir=/home/mosty/mysql
the error is
Code:
Installing MySQL system tables...
100315 20:07:27 [Warning] Can't create test file /var/lib/mysql/mosty.lower-test
100315 20:07:27 [Warning] Can't create test file /var/lib/mysql/mosty.lower-test
[code]....
You can try to start the mysqld daemon with:
shell> /home/mosty/mysql/bin/mysqld --skip-grant &
and use the command line tool /home/mosty/mysql/bin/mysql to connect to the mysql database and look at the grant tables:
shell> /home/mosty/mysql/bin/mysql -u root mysql
mysql> show tables
I'm getting close to ordering the components for a new machine based on the AMD Deneb quad core and had one last question.I'd like to try a little careful overclocking, not only for the performance increase but also to learn how. Nothing extreme, no gaming, just whatever I can get with good stability with the stock heatsink and fan.I was going to get 8GB on 2x4GB strips but they are all CAS latency 9. The MB has 4 slots for a total of 16GB capacity. Would I be better off going with 4x2GB strips and try to get a lower latency strip like maybe 7?
View 5 Replies View RelatedAs I am trying to understand if there are any advantages using a kernel optimized to have low latency for the desktop, it would very helpful if anyone using one could give me his opinion. I read about the liquorix kernel and found a controversy and used google to find more information.
View 2 Replies View RelatedI tend to use commands like 'aptitude search $something' or 'dpkg -S /usr/bin/command' (some command/variable in both) or 'apt-file search $something' and all/or many of its brethen. I do run updatedb every now and then but that command is for the overall health of the system similar to tracker perhaps (but not running continously like tracker and the daemon).
What I'm looking for is, if there is a way to get the package list (installed and otherwise) updated aggressively so that whenever I use any combination of aptitude or dpkg I get better response from the system. From what little I understand, aptitude or dpkg or somewhere there would be some sort of index/database where the current state of package availability and system state would be recorded. If there is a way that this could be improved upon would be nice to know. If there is some experimental package or road which the debian folks are looking for in the future so this latency can come down.
is there a realtime or low-latency kernel in a repository somewhere for OpenSUSE 11.4? I know I can just compile a rt kernel, but that's a bit tedious and I'd like to avoid it if possible.
View 9 Replies View Relatedwe are setuping high-performance web farm with 4 ubuntu servers (all 10.14 LTS 64bit, i5Core CPU, 16GB Ram). One server is "database" server with mysql installed, three servers are "webservers" with tomcat installed. All three webservers have public IP and are connected directly to internet by eth0 (onboard network card) and are connected to switch that is connected to database server by eth1 (pci network card). All servers has stardard instalation with no special modules/programes installed.
Web servers are already under load, but only on about 10 requests/minute. After several hours in production, strange thing happened - one of the web servers (each time another one, so it is happening to all of them but not at once) starts to have pings to database (that is connected directly on LAN) = 100ms (other two servers still has like 0,02ms). Pings stay high until we do /etc/init.d/networking restart, after that it is fixed and pins are again low again. Another strange think is, that when we let ping running for some time, it is slowly dropping from 100ms to 1 ms and then again jumps to 100ms (exactly to 100ms always) and again starts dropping - so it is cycling over and over again (one cycle takes about 2 minutes).
We were trying reconfigure network, play with switch (the same situation was happening even without switch when there was only one webserver and one database server directly connected), disable IPv6 but nothing helped. The only thing that we discovered is that it has to be caused by network configuration.Do you have any idea what can cause it? We went through systems logs but found nothing suspicious (at least according to our understanding).
It's an eMachines T2899 desktop, FIC AU31 motherboard, nForce2 chipset, AC97 sound (integrated), running Xubuntu 10.04 (wubi install), 2.6.32-22.I've got terrible sound latency (about one second between actions and sound) in some programs.Flash in both firefox and chrome (including ..... videos) and ZSNES (SNES emulator) are two offenders, as is Audacity.Videos played in the default "movie player" and VLC play with no delay, though.I've been told it could be an issue with the ALSA buffer size, or pulseaudio introducing latency... but I've no clue how to go about fixing it.Upon using the SNES9X emulator (which allows for choice of sound system)... Portaudio causes laggy emulation and bad sound latency. Open Sound System plays fine. SDL causes laggy emulation and bad sound latency. ALSA plays fine. Pulse Audio plays fine."sudo apt-get remove --purge pulseaudio" did nothing, so I reinstalled it just in case.
View 4 Replies View RelatedI'm looking for a program that can measure disk latency. I would prefer one that could do it on a raw device. Also reporting average and max latency would be a plus.
Anyone know a program that can do this?
JIt was easy to check in Windows, but I just wanted to know if there's a way to check if Ubuntu is utilizing both cores of my processor (Pentium Core 2 Duo).
View 9 Replies View RelatedI am attempting to Run Ubuntu 10.10 on a system with 128 CPU cores (64 dual core processors), but Ubuntu is only detecting 32 cores. I've looked and looked and cannot find any information on this topic; is there a core limitation in the kernel configuration that I missed? Currently I am using Ubuntu 10.10 Desktop, would I have more luck with 10.10 Server or another version?
View 9 Replies View RelatedAnybody knows How can I get the number of cores of a machine?I know that I can use POPEN and get the stream of this:
Code:
grep -i 'processor' /proc/cpuinfo | wc -l
But, I think that a simple method to do this.
My large ext4 / filesystem seems to cause huge latency problems when writing a large file. For example, if I use split to break up a 40GB file into DVD-sized chunks, my browser becomes unresponsive, and it can take several seconds for Gnome terminal to respond to a mouse click.
I installed LatencyTOP, and it shows jbd2_log_wait_commit as the big offender, with Chrome waiting on that function for over 31000ms (or 31 seconds). I tried remounting / with barrier=0, but that didn't help. My hard drive is a WD20EARS-00MVWB0 2TB SATA disk. I recently switched my BIOS from IDE emulation to AHCI mode, but that didn't help. I tried running split with ionice, and that does help, but the system still isn't responsive as it should be, and I'd hate to have to remember to ionice every large write. Here is some relevant stuff from dmesg:
Code:
[ 1.294068] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 1.294096] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 1.294119] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[code]....
I'm running kernel version 2.6.38.8-35.fc15.x86_64.
I have a Macbook running Ubuntu Karmic and I have been asked to DJ (amateur to the MAX) a friend's wedding next weekend. I don't have the coin to spend on a Mixer so I can run my mic and laptop through my amp so I figure I'd just run the Mic into the mic input on my Macbook and let the laptop do the mixing for me.Well, I added the loopback module to Pulse and inserted a command to have it auto start:
Code:
pactl load-module module-loopback
Code:
[code]....
I just installed Maverick Studio on a new hard drive, and am using an NVIDIA GeForce 7300 LE GPU. If I boot into the 2.6.35-22-generic kernel, everything runs fine, but if I try to boot into either the 2.6.35-20-Low Latency, or 2.6.33-29-Realtime kernels (installed from Synaptic), the computer boots straight to a command prompt instead of the desktop. Does anybody know what causes this? I need to be able to use one of these kernels for doing music production.
View 1 Replies View RelatedI'm experiencing massive latency/unreachable problems on my Linux machine. It's true for all network connections, here's an example of me trying to ping my router:
PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.
64 bytes from 192.168.0.1: icmp_req=1 ttl=64 time=15115 ms
64 bytes from 192.168.0.1: icmp_req=2 ttl=64 time=14107 ms
64 bytes from 192.168.0.1: icmp_req=3 ttl=64 time=13107 ms
64 bytes from 192.168.0.1: icmp_req=4 ttl=64 time=12107 ms
64 bytes from 192.168.0.1: icmp_req=5 ttl=64 time=11108 ms
[Code]...
I've tried now with both the maverick default kernel and 2.6.37-rc5 kernel (both 64 bit), same result. If I take the card up and down (ifup, ifdown) performance is restored for a little while, then it's back. I've tried changing cable, network card and router port but no luck.