The speed at which a program runs

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6 views

Calcualte the correct MBit/s in my speedtest

I know wget is usually showing the speed in a summary, but in my small OpenWRT shell. I want to test how long it takes to download 100MB with t=$(date +"%s") wget ...
9
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1answer
107 views

Fastest way to delete duplicates in large wordlist?

I need to deduplicate a large wordlist. I tried several commands and did some research here and here where they explain that the fastest way to deduplicate a wordlist seems to be using awk. awk ...
31
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4answers
2k views

Should I care about unnecessary cats?

A lot of command-line utilities can take their input either from a pipe or as a filename argument. For long shell scripts, I find starting the chain off with a cat makes it more readable, especially ...
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1answer
99 views

How low can I go on RAM?

I have some old PCs runnning on my business. And by old I mean PENTIUM-3 800 MHZ and AMD DURON 950 MHZ, with 256MB RAM. They are running my business software today on Windows XP. I want to run Linux ...
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3answers
4k views

ulimit & rlimit in Linux, are they the same thing?

I see people use the terms ulimit & rlimit interchangeably, can I say they are referring to the same thing?
19
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6answers
11k views

Is there a parallel file archiver (like tar)?

Is there something out there for parallel archiving of files? Tar is great, but I don't use tape archives, and it's more important to me that the archiving happens quickly (with compression like ...
1
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0answers
29 views

How does performance measurement tool 'perf' actually work?

a perf tool which accesses the performance counter registers of an machine and gives out metrcis to user to analyse the system performance what i am curious about is , when i read the parts of ...
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1answer
25 views

Python processes appearing and disappearing in top

I concurrently launched around 12 Python scripts on a 24-core server (Ubuntu 14.04 LTS x64). Each of Python script takes around one hour to complete. I see in top that they appear quite sporadically, ...
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3answers
10k views

is there an open source tool to measure cpu performance?

I have used many times ab for measuring web performance, hdparm for measuring hard disk performance and netperf for measuring network performance. But I didn't find any tools to measure cpu ...
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2answers
1k views

Ubuntu is running slow

I'm not sure since when it became slow, but I think after I did apt-get update. Here's my machine details: I can see from the system monitor that the CPU is working hard specially when I run Chrome ...
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1answer
4k views

Defragmentation of LVM2 logical volumes

Question: Is there a tool supporting de-fragmentation of LVM2 logical volumes ? (Making their extents into consistent sequences) Preferably by defining desired order of extents (something like ...
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2answers
701 views

Why I can not use all the 100% potential of CPU?

I am using my computer clusters to run a MD C program but I can not use full potential of those clusters. But the this node have 16 CPUs and I also only give 15 jobs for those CPUs. But I can not ...
4
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3answers
279 views

Grep all at once

The script I have receives arguments and needs to grep through another file. Script loops through every argument. Is there a way to collect the arguments in a single search string and grep with OR ? ...
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0answers
20 views

How can writing speed equal to reading's over nbd and ram disk

My testing is under two nodes whose communication is over nbd,and each node uses ram disk as local storage.The result is that reading speed can reach the bandwidth 6GB/s,while writing speed is only ...
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3answers
95 views

Linux, SSD and swap

This article suggests not to create a swap space on an SSD drive in order to reduce its wear. On the other hand, it suggested here that swap space positively affects performance. Would it be a better ...
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2answers
75 views

how to go mouseless [closed]

I would like to improve my efficiency. I recall seeing some tool to use gui applications on linux with the keyboard, but I do not recall much else about it! Please advise how I can go mouseless(for ...
0
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3answers
323 views

The performance difference between a command that does the same thing

What is the difference? It is performed in the same? tar -czf files/compressed/gzip/archive.tar.gz -C files/original . tar -c -C files/original . | gzip -1 > files/compressed/gzip/archive.tar.gz ...
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1answer
57 views

how to disable access time settings in Debian linux

Performance Best Practices for MongoDB implies that: Most file systems will maintain metadata for the last time a file was accessed. While this may be useful for some applications, in a ...
3
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1answer
30 views

Cache atime writes

Is there a way to set atime writes to be cached for a very long time? I need atime (that is to say, relatime won't cut it), but I don't want it to effect performance so much. Data loss in of atimes ...
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0answers
34 views

where to compress=lzo, btrfs with virtual disk images, with their vm's internally using btrfs

I've been using compress=lzo on my btrfs volumes, because I read this fast compression method actually increases drive performance. (Haven't tested myself.) I'm starting to use ...
4
votes
1answer
2k views

Audio/video out of sync when playing MP4s in mplayer

When I try to play MP4 files in mplayer, after a few seconds I get the "Your system is too SLOW to play this!" warning and the video starts lagging behind the audio. It only happens with MP4s, and ...
0
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1answer
42 views

btrfs on LVM on LUKS - one LUKS container performs WAY better than the other

I have 2 LUKS containers, one with default OpenSUSE installer settings, another one with -h sha512 -s 512 -i 5000 and detached header. On top of each of them there is LVM - one with only 1 OS volume ...
0
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1answer
15 views

Is it possible to have some shared objects be preloaded asynchronously during boot?

If I recall correctly, the same shared object is not loaded into memory twice when it's used by multiple processes. Is it possible to have some shared objects preloaded into memory asynchronously ...
0
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1answer
68 views

Wordlist/dictionary generation for penetration testing

How can I generate a dictionary of words containing 8-16 of alphabet characters ([a-zA-Z]) with low memory?
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0answers
51 views

How fast is a process reading/writting virtual memory?

So, we have top, htop, iotop, iostat, vmstat, etc, to measure many different things on Linux, but how can one measure how much MB/s a process is reading and writting to/from RAM, i.e., virtual memory? ...
0
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1answer
344 views

Why Linux games are less performanced than Win 7?

I had Windows 7 x64 and now I have Ubuntu 14.04 on notebook HP 4535s. I expected games to be faster in Linux than on Windows because of fewer machine requirements. But it isn't so... E.g., games via ...
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5answers
3k views

Any tricks to speed up sort?

For example for bzip there is pbzip, a parallel version of bzip. Is there any such parallelization tools for sort to improve performance?
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0answers
9 views

Turn off slide effect on kde menu

I have a remote computer via a nomachine connection. I use kde on the remote machine. How to turn off slide effect in KDE menu?
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1answer
49 views

Stable timing for shell scripts?

The run times of scripts vary quite much. I would like to find similar time -function as Matlab's timeit, described here. For instance, I am evaluating these commands here about counting quickly ...
0
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3answers
3k views

Console CPU utilisation chart

I need to monitor CPU and network utilisation from a terminal. For network traffic, I have found the perfect tool: slurm. It gives me a moving chart. It gives me an nCurses-like UI I can use from a ...
0
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1answer
37 views

How can I track long-term system performance in Linux (Debian)?

I love the RRD graphs that pfSense provides. Is there a package for Debian or a generic tool that can do the same for my Debian box?
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1answer
39 views

Does orca + RICHPse work on Solaris Containers or local zones?

I have just attempted to get RICHPse version 3.4 running on a Solaris version 10 Sun M5000. It seems to run on the global zone but not on the local zones. On the local zones RICHPse just fails ...
7
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2answers
13k views

rsync is very slow (factor 8 to 10) compared to cp on copying files from nfs-share to local dir

I have a freshly installed Ubuntu-server which is ought to be the new backup-server for our VM-storage. The server has 4 nics, 2 of them 10Gbit (in fact an intel x540-T2 with the newest driver ...
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0answers
17 views

How can Profile/Benchmark ram performance?

Effectively I would like to know if my memory hardware it a bottleneck of my system performance. I am dealing with really old hardware (late 2000), mind you. If there is room for improvement I would ...
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1answer
33 views

Performance of `tar -xf` (block size related)

I'm recently working on optimizing the performance of tar -xf, i.e. untar a file. I notice that under default settings, tar -xf calls writes to write 10 KiB output at a time in chunks. However, this ...
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0answers
27 views

Delaying packets with libnetfilter_queue

From my Raspberry Pi configured as an access point, I set the following rules: sudo iptables -I FORWARD -p tcp --sport 25 -j NFQUEUE --queue-num 0 sudo iptables -I FORWARD -p tcp --sport 80 -j ...
92
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7answers
32k views

Why use swap when there is more than enough free space in RAM?

Using swap space instead of RAM can drastically slow down a PC. So why, when I have more than enough RAM available, does my Linux system (Arch) use the swap? Checkout my conky output below: Also, ...
4
votes
1answer
527 views

GNU/Linux, IO performance problems

I have some problems with my system performance. As I was adviced here, I used sar: $sar -u 5 and found out that the problems are caused by a low HDD performance, as I supposed (high %iowait). ...
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0answers
50 views

Why is my UDP bandwidth significantly lower than TCP bandwidth in iperf

I am running a simple bandwidth test between two VMs using iperf. I am getting very different bandwidth reading for TCP and UDP where the UDP bandwidth is terribly lower than TCP. TCP: ...
0
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1answer
60 views

What is the impact on system performance when kernel debug info is enabled?

In order to debug kernel or use tools like stap (https://en.wikipedia.org/wiki/SystemTap) kernel must be compiled with full debugging information included - namely option CONFIG_DEBUG_INFO has to be ...
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3answers
153 views

Linux & Linux-Software: Advantages of a multi core processor [closed]

I plan to get a new notebook and try to find out if a quad-core processor gives me any advantages over a regular dual-core machine. I use common Linux Distributions (Ubuntu, Arch etc.) and mostly ...
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1answer
39 views

Show CPU core usage for parent process and its child processes

Is it possible to display CPU core usage just for a single process and its child processes on Linux?
0
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1answer
47 views

Relaunch an app if it freezes

Yesterday I successfully managed to make a kiosk from Ubuntu Server. I'm going to use it to rub some web application that will run non-stop. However, in some cases, duo to lot of js animation I'm ...
15
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3answers
541 views

What is the IPsec bottleneck in Linux?

I am trying to compare the performance of several network security protocols between two hosts connected in Gigabit Ethernet. My goal here is to see if I can saturate my bandwidth, and if not, what ...
1
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1answer
138 views

Least resource-consuming Linux OS to run just Chrome

I've developed some application which uses a browser in order to run. The usage of the browser is simply for the GUI which is built with html/css/js (there are lot of js animations). Currently, the ...
4
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2answers
83 views

What is actually the speed reported by dd?

I always thought that when doing: dd if=/dev/sdx of=/dev/sdy the report which is displayed once the command finishes, such as: 79304319+0 records in 79304319+0 records out 40603811328 bytes (41 ...
0
votes
1answer
727 views

NFS server optimization for maximum performance

I'm looking for maximum of performance for a NFS mount. I'm on local network, it could be completly unsecure, the performance is the most important in my case. What I already found : In /etc/export ...
2
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0answers
210 views

Linux Mint 17.1 Cinnamon is slower in computer than in Virtual Box

After some months working in a VirtualBox VM with Linux Mint (the host as a Windows 7), I've finally installed Mint 17.1 Cinnamon on the same computer. And the experience hasn't been good. The fact ...
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4answers
134 views

any large inode size benefits? (ext4)

From some foggy memories I thought I would "improve" the default settings when creating a Linux partition and increased the inode size to 1024, and also turned on -O bigalloc ("This ext4 feature ...
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3answers
487 views

How to calculate the memory consumed by a “C” program in linux

I have written two C programmes one is using function pointer, and the other without function pointer. Now i want to know the memory consumed by the two programmes , to see how memory can ...