The speed at which a program runs

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30 views

Will SSD swap improve performance?

I am wondering if i have only 4GB ram and somehow(virtualbox,browser) isn't enough and i cannot proceed to upgrade(due to ultrabook and soldered memory) will swap held in SSD help the overall ...
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0answers
15 views

How does the proc/diskstats work to present that values? And for proc/stat and meminfo?

I am trying to get the diskstats data by same way that the file does. Is there any way to reach that values without reading that file? How the values are placed there? Is there any ".c" file that ...
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0answers
13 views

Transmission in idle or slow speed

I am running Transmission on Raspbian via the command line. transmission-daemon is running fine as well as downloading. However after the download is finished and seeding should start, the Raspberry ...
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0answers
33 views

How to track down the source of I/O spikes?

I am using Linux as a desktop, and keep getting seemingly random I/O Spikes. The machine becomes unusably slow. At first I thought it was just that I don't have enough memory. But looking at the ...
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0answers
11 views

Congestion Control algorithm performance testing in FreeBSD

I am working on implementation of a proposed modification of TCP Congestion Control algorithm that would allow to improve it (the CC) by adding a dynamic bandwidth estimation. I have been able (with ...
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0answers
39 views

Set the TCP window scaling option to 4 & the TCP window size to 65535 [closed]

I want all TCP packet (linux system) to be sent with: TCP window scaling option set to: 4 TCP window size set to: 65535 (0xffff). How I can configure my linux system to do that?
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1answer
71 views

AIX CPU usage - how to know how many CPUs running?

Over AIX 6.1 - I do see the following output, it says I have 16 Max Physical CPUs; but there are only 8 active - why is that? The system will use the remaining 8 if needed? Or are they disabled? # ...
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2answers
82 views

Besides cache, what does the Linux kernel use significant amounts of memory for?

My computer feels really sluggish. According to free, I have only ~200M RAM left and more than a gigabyte had to be swapped out. I know that it is good if memory is used for caching but this looks ...
6
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1answer
359 views

Does ionice work with the deadline scheduler?

My Debian Wheezy systems use the deadline scheduler. I'm accustomed to using ionice to reschedule the I/O priority of disk-intensive jobs at busy times, and anecdotally this seems to help (but I ...
4
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1answer
1k 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 ...
2
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2answers
43 views

Make rsync move (not copy) files on local file system

Can I make rsync to move large amount of files instead of copying them when on local filesystem? I would like it to behave like improved mv command. I know about --remove-source-files option but ...
54
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3answers
96k views

How do you empty the buffers and cache on a Linux system?

Prior to doing some benchmarking work how would one free up the memory (RAM) that the Linux Kernel is consuming for its buffers and cache?
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0answers
24 views

How to generate graphs from lmbench results?

I need to use the lmbench benchmarking tool to get the system performance statistics. I am able to execute and run the results. In the results folder this is a MakeFile with this information # ...
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0answers
34 views

Linux desktop (Mint MATE) requires reboot every few days

Summary After a few days of uptime, my system starts getting slow. How can I determine the cause and fix it? Opening a Youtube video or some web-pages will freeze Firefox for an increasing amount of ...
2
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2answers
43 views

Pipe Viewer - Progress monitor performance consequence

I am writing a batch script to sort through gigs and gigs of data. All of the data is text but the script will take a long long time to execute. I would like to give some visual indication that the ...
0
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1answer
619 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
119 views

Why adding swap space is the slowest part of the booting process? [closed]

I can see that adding Swap space is the slowest part of the booting process. Why? I actually have ~4GB for swap and 2GB RAM memory. dione@saturno:~$ dmesg | grep -C 4 swap [ 2.179979] input: ...
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1answer
54 views

Understanding high load average with vmstat, mpstat, sar, and top

I am trying to understand the load average on my system when idle. Here are some results after the system has been running for a few hours, with almost nothing installed. vmstat root@arm:~# vmstat ...
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0answers
82 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 ...
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2answers
3k 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?
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0answers
20 views

JVM low-memory tuning

What command-line options would provide the lowest memory-footprint JVM, in OpenJDK, or possibly other JVMs (Linux/Debian)? I'm willing to disable JIT, live with slow or choppy garbage collection, ...
2
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1answer
138 views

Understanding why such a discrepancy in network transfer?

Summary: I can't understand a peculiar discrepancy in network transfer. Why is there such a discrepancy in syncing from one machine to the other and vice versa? Also: Given the maximum network ...
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4answers
2k views

Why is writing SLOW on raw device, and FAST on filesystem (USB key)?

I have a USB key (PQI U822V-Speedy 32G) that I am trying to benchmark quick'n'dirty on Linux. I'm testing write bandwith. dd on raw partition I created a partition starting at sector 2048, then did ...
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1answer
32 views

Overhead when relocating a directory to a different file system using a symbolic link

I need to relocate some frequently accessed files to a different file system. The simplest way of doing this is to move the directory containing the files to the new file system and creating a ...
0
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1answer
411 views

Simple bash script taking too long to execute

I wrote the following function in my .bashrc for use instead of rm * : function re() { cp . -R /home/glset/ritwik/trash/ rm * } It works .. but it is very slow. Even for small files it takes ...
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2answers
48 views

How does one determine when a process or machine is IO bound?

I have a node.js process which writes to many different sqlite databases. Sqlite can handle only one concurrent write per database, which is fine since there will be only one write per database at a ...
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84 views

'nc' using ~100% CPU when transferring a FIFO file

On the server which is always connected I’m using this in a crontab: @reboot nc -k -l 1337 < /tmp/fifo.fifo On the client which is not always on the network or switched on I’m using this ...
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3answers
8k 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 ...
0
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1answer
162 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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1answer
104 views

Does dm-multipath schedule I/O?

I have a multipath device I'm interested in: [root@xxx dm-7]# multipath -ll mpathf mpathf (3600601609f013300227e5b5b3790e411) dm-7 DGC,VRAID size=3.0T features='1 queue_if_no_path' hwhandler='1 alua' ...
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1answer
86 views

how to choose appropriate linux hardware - poor graphics performance

I can't believe I am asking this question here myself. Apologies if this is not the right place for this question. I've been using linux since 1996, SuSE version 4.1... And yet I am still not able ...
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3answers
2k 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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5answers
2k views

How to get better desktop performance in linux?

Normally I do not care much about desktop - performance, since my servers do not run any gui. But at home I run some older hardware (Pentium) which gets sometimes very sluggish (mouse-movements in ...
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3answers
73 views

Optimise a shell script / command to delete files

I'm running Magento and it doesn't clean up old session data, so I need to clean it up with a shell script / cronjob: 0,30 * * * * /usr/bin/find /var/www/magento/var/session -name 'sess_*' -type f ...
5
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3answers
985 views

What is the expected performance of obnam? Or: why is it so slow?

I've been playing around with obnam these last few days, and although it looks very promising and seems to offer basically everything I ever wanted in a backup tool, I am pretty disappointed in its ...
0
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1answer
819 views

How do I create a RAM disk on Linux Mint?

I am running a package that adds data to the end of 140–300 files each time through the process. I'm thinking of moving the process to a RAM disk, and using rsync to copy it back when done. My goal ...
0
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1answer
26 views

Solaris prstat - definition of “recent” time used in percentages

The man page for prstat (on Solaris 10 in my case) notes that that CPU % output is the "percentage of recent CPU time". I am trying to understand in more depth what "recent" means in this context - is ...
0
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1answer
83 views

Powerful Workstation

I heard about ILM's (Industrial Light and Magic) workstations on which they create models and scenes for a lot of different movies. They have workstations with more than 1024 GB of ram and a lot of ...
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98 views

SEGFAULT error 4 in libX11 on another X display caused by War Thunder

I read tons of info about performance boosting for linux gaming. One of them is to run games on a separate X server. After hours of search and tries, I ended up with something "working" for most of ...
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2answers
781 views

What is the most accurate way to measure disk read/write speed for an OpenVZ VPS host from within the host itself?

CentOS 6.x | OpenVZ I have an openvz VPS host and would like to measure disk read/write speed. Historically, on other physical systems, I've ran hdparm to collect this information. I haven't been ...
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0answers
55 views

Variations in Ubuntu 12.04 /usr/bin/time statistics

I have a command line tool which I run on Ubuntu 12.04.5 LTS. I need to calculate the cpu time for this program. I have been checking /usr/bin/time function. command: /usr/bin/time -v -a -o ...
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0answers
56 views

Fixing terrible performance when watching/reading video and writing video files to disk

I have had this issue for quite some time and tried many times to fix it on my own and it always fails. IP schedulers, ionice and things like that always yield no result. I even went and bought an ...
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2answers
397 views

Optimizing logical sector size for physical sector size 4096 HDD

With many new hard drive disks the physical sector size is 4096. Would it be possible to make the system use a logical sector size of the same size, rather than the default logical sector size of 512? ...
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0answers
18 views

Using `perf` repeatedly with file input

perf can be used to analyze the performance of a program. Say you want to test the performance of a program prgrm, with input from a file, you can run: perf stat prgrm < inp.dat Now when you ...
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0answers
26 views

run netperf without IP address available

I have DPDK set up, with two NICs taken over by DPDK, i.e. the interfaces are not visible to userspace applications. Now, I need to run netperf/iperf to measure throughput performance of port-to-port ...
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0answers
31 views

netperf: run with no control connection

Trying to run netperf without setting up a control connection between netperf and netserver: client% netperf -N -H 10.0.0.2 ... netperf: send_omni: connect_data_socket failed: No route to ...
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3answers
4k views

Measure pipe throughput in the shell

There is a shell command that allows to measure how fast the data goes through it, so you can measure the speed of output of commands in a pipe. So instead of: $ somecommand | anothercommand you ...
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2answers
66 views

How to make a filter more efficient

I've created a script to compare a list of users from a MSSQL database against a list of disabled AD users. The tool we use for AD authentication returns data in the following format (with plenty ...
3
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1answer
440 views

Rsnapshot via SSH speed issue

I am trying to backup bunch of desktops running RedHat 6.4 (i86_64) LVM on the top of ext4 to our file server running RedHat using rsnapshot and ssh. I am on 1GbE. I am finding the speed of the first ...
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3answers
127 views

Can I make [ $(($1 % $check)) -ne 0 ]; be more performant and not be killed?

If have the following code which works for up to 13 (line 2) in a few seconds but when I try and do upper teens and 20 it gets killed after a couple of minutes. divisible_by () { for ((check=2; ...