The speed at which a program runs

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1answer
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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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1answer
581 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 ...
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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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1answer
28 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
100 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 will be faster than on Windows, because of less machine requirements. But it isn't so... E.g. games via ...
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4answers
1k 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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3answers
55 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 ...
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3answers
847 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 ...
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1answer
641 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 ...
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1answer
18 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 ...
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1answer
74 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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32 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 ...
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 ...
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2answers
645 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
30 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
30 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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0answers
48 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
117 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
16 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
18 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
21 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 ...
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1answer
407 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
122 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; ...
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2answers
43 views

How to find the number of bytes rewritten to a folder hierarchy?

I want metrics for how much writing and reading have been done to a folder. vmstat -d gives metrics at the whole disk level. iotop will give per process rw stats. But how can I find out how much ...
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0answers
95 views

Virtualized Debian Jessie: slow booting / shutting down :(

I have a Debian 8 (Jessie), cat /proc/version says: Linux version 3.16.0-4-amd64 (debian-kernel@lists.debian.org) (gcc version 4.8.3 (Debian 4.8.3-16) ) #1 SMP Debian 3.16.7-ckt2-1 (2014-12-08) ...
45
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2answers
71k 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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2answers
59 views

Why is userspace slower than the kernel?

I've heard that FUSE-based filesystems are notoriously slow because they are implemented in a userspace program. What is it about userspace that is slower than the kernel?
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1answer
41 views

Where is NMon cron job for AIX?

While trying to know where is NMon job configured to run; I do find that it's NOT listed on Crontab (using crontab -l). BUT - the job is currently running as expected, which is weird. See the ...
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1answer
59 views

Is it useful for a proxy to buffer less data than Linux RCVBUF can?

I am looking at how HTTP proxies and reverse proxies deal with slow client problems. The idea is that the upstream server only have a limited slots for clients and if the client is slow to receive ...
2
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0answers
30 views

Why does my fresh Debian have a high latency?

The time between clicking and seeing a response is very high. Typing looks very funny, and makes me feel queasy. I think there's about 50-20ms "extra". I would expect a top notch linux distro to have ...
3
votes
1answer
128 views

How does netstat command fit in various layers of TCP/IP model in the performance diagram?

netstat command is useful to, Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. Now, I was reading about the Linux performance ...
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0answers
92 views

Increasing ulimit stack size benefits?

Hello I'm new in Linux and at my work I have a server that runs a banking software. The company that made the software said that the stack size should be set to unlimited. Does this make the software ...
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11answers
8k views

the lightest way to have a GUI in Linux? [closed]

I have been using Gnome and KDE for a while, and I am now running Compiz standalone... Regarding system resource, I think the most heavy ones are feature-rich desktop environments (Gnome, KDE), then ...
2
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1answer
32 views

Why is my computer sluggish after downloading a lot?

When I download a lot of data (e.g. 3GB) in one go, using a program such as Transmission or Wget, progressively during the downloading, and after it has has finished, the computer always seems ...
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0answers
49 views

How to diagnose CPU performance problems?

Recently I bought a new netbook based on AMD A4-1200 CPU and installed Linux Mint 17 with XFCE. RAM is 4GB So, testing some of my programs, I found very strange behavior. On random intervals, the ...
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2answers
166 views

Disk busy is close to 100% and iowait is 0,0% on SunOS, how can it be possible?

During monitoring of SunOS5.10 machine I noticed strange behavior: Disk busy is close to 100% Disk waiting time is 0,0% Primary purpose of this machine is running application server on jvm. This ...
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2answers
2k 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 ...
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3answers
1k views

Why is coreutils sort slower than Python?

I wrote the following script to test the speed of Python's sort functionality: from sys import stdin, stdout lines = list(stdin) lines.sort() stdout.writelines(lines) I then compared this to the ...
2
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1answer
60 views

What could be done to make Embedded Linux boot faster?

My team is developing a software for a Embedded Linux solution. The problem we are facing is that it takes too much time for the system to be ready to start running our desired apps (that is, too much ...
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1answer
91 views

why doesn't iozone generate output file?

I'm using iozone3 for tesing, on Xamin (an Debian-based OS). When I enter iozone command, for example iozone -Rab output.xls, the test runs successfully. But after running the test (after displaying ...
0
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1answer
86 views

rsync: Copy speed decreases while syncing two directories

I am using rsync on fedora 20 to sync my directories. I am using the command below:- $ rsync --progress -a srcDir DestDir But, as rsync copies files, copy speed decreases significantly. Here is my ...
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34 views

Xorg consumes CPU, RHEL 7 fresh install

I've installed RHEL 7 with default settings. I wonder why Xorg consumes 30% of my CPUs. How can I know what's wrong and how to fix it? HP DL360p Gen8, dual Xeon E5-2640
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2answers
28 views

Optimize file layout for minimal seek in specific situations

Starting VLC is slow on my system. The reason: it reads more than 1000 different .so files. Is there a way to make it read those files faster? I think if all the files followed immediately after each ...
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0answers
43 views

Properly mount a windows share to move files on the mountpoint

This question resulted from a question of mine on stackexchange. I mount a windows share with mount -t cifs -o ...
1
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1answer
174 views

Find the process which is taking maximum CPU usage if CPU usage is more than 60%?

I am trying to measure the cpu usage of my ubuntu machine and if the cpu usage is more than 60%, then I need to find out the process who has the highest cpu usage and then send out an email saying CPU ...
1
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1answer
51 views

Disk is a bottleneck. Background processes make things worse. How to improve responsiveness?

Often, the bottleneck of my laptop is the disk. When doing some disk-intensive computations, automatically-started background processes like updatedb, find /something etc. kick in, making things even ...
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3answers
52 views

Software RAID10 setup writes small files extremely slowly, is this normal?

I have a software RAID-10 setup on Linux 3.16.6-203.fc20.x86_64, with 1.2 metadata and the default chunk size (512K): $ cat /proc/mdstat md0 : active raid10 sdc1[4] sdb1[0] sdd1[2] sde1[3] ...