The speed at which a program runs

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3
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1answer
1k views

Linux: How to check whether a process is slowed down by other running processes

I have one process running on a RHEL 6.3 machine. Somehow this is taking a longer processing time than the same process running on another machine. How is it possible to know why this process is ...
7
votes
3answers
10k views

Grep in couple thousands files

I have directory with cca 26 000 files and I need to grep in all these files. Problem is, that I need it as fast as possible, so it's not ideal to make script where grep will take name of one file ...
2
votes
1answer
867 views

Is there any tool to view live statistics about a Radeon GPU?

I've checked out GPU usage monitoring (CUDA), but are there similar tools for AMD/ATI cards? Or kind of universal tools? I want to check out if my applications use the 256 MB of RAM of the video card ...
1
vote
1answer
638 views

numfsbufs and mount/remount of File Systems

What is the right the procedure to set the numfsbufs parameter? The current value of the parameter is 196 App_Server:>ioo -o numfsbufs numfsbufs = 196 The details of the server (prtconf ...
0
votes
1answer
2k views

What does high, low, negative and constant values from pidstat command mean?

I needed information on the following: Can you please tell me the inference for the following in terms of high, low, negative and constant values from pidstat command in Linux. kB_rd/s, kB_wr/s, ...
0
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1answer
164 views

Is my approach to performance testing in Linux environment correct?

I want to do performance testing in a Linux environment for a C++ application. I need to measure the CPU & Memory usage of the application. This application is a multi-threaded application. In ...
0
votes
1answer
160 views

How can I look at recent system activity to figure out what caused a huge slowdown? [closed]

I'm running CrunchBang Waldorf with OpenBox on a Lenovo e420. I made the switch from Windows a few months ago, and have had no problems with performance since then. Everything runs nice & fast. ...
5
votes
3answers
6k 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
373 views

X high CPU when using Java applications

Only recently, my Freemind program has become extremely sluggish and unresponsive (big lag) when moving my mind map around. I use Arch Linux with xfce4. Freemind is made with Java. If I move the mind ...
5
votes
2answers
836 views

Why do systems become slow when doing massive writes to disk?

I want to know why systems become slow when writing mass data to disk. I think that for system to become slow, there should be some issue with CPU. But write is only I/O bound. Do hardware ...
0
votes
1answer
646 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 ...
5
votes
7answers
2k views

How can I defragment my SSD on linux?

This page demonstrates that defragmentation is beneficial for SSDs. I suppose this type of defragmentation has to be trim-aware, so as to preserve the life time of the disk. How can I do that on ...
6
votes
2answers
2k views

Inotifywait for large number of files in a directory

What I want to do is, to monitor a directory (not recursive, just one) for new files created and append those files to one single big file as they are being written. The number of files that are ...
2
votes
1answer
1k views

Measurement of free ram through /proc/meminfo with ramdisk (initrd)

I am booting a disk image via PXE, it is a full system on an initrd ramdisk. I would like to measure the actual free memory of the system (not including buffers and file system caching). I was told ...
7
votes
2answers
5k views

CPU usage of KVM

I have a linux host with 4 KVM linux guests. All the guest are pretty much idle, having a load of <0.1 inside the guest. Now, if I do a top on the host, each KVM process is using something about ...
5
votes
2answers
3k views

rsyslog drops messages excessively

We have a CentOS machine acting as our syslog server. I recently noticed that the machine has been dropping large numbers of syslog messages at times. We have over 250 routers and switches, as well ...
5
votes
1answer
1k views

How does irqbalance determine which package to use?

irqbalance --debug shows the following: Package 0: Core 0, 2, 4, 6, 8, 10, 12, 14 Package 1: Core 1, 3, 5, 7, 9, 11, 13 When I run network applications, it seems like IRQs are being handled by ...
2
votes
2answers
809 views

why is filesystem intensive script not faster on ram disk

I have a script which creates a lot of files and directories. The script does black box tests for a program which works with a lot of files and directories. The test count grew and the tests were ...
3
votes
1answer
2k views

Does encrypting my whole Lubuntu slow running programs down?

During the installation of Lubuntu I chose to encrypt my whole HDD (not just the /home folder). Now it feels like my system has slowed down a lot. Especially the startup time of programs increased. ...
0
votes
1answer
225 views

udevadm slow boot

After I upgraded from Slackware 13.70 to 14.0, when the machine is booting, it takes it 15 seconds to execute this line: /sbin/udevadm trigger --action=add I understand, that it tries to detect ...
0
votes
1answer
235 views

Open screen in terminal after user login [duplicate]

When a user logins to my Debian server using e.g. Putty, I need to perform the following: It will automatically execute command screen -r MyWindow, and the user won't be able to leave the screen ...
6
votes
1answer
1k views

Determining LVM Extent numbers for given file

I'm currently engaged in a non-work related homework exercise. I have an ext4 filesystem sitting on a logical volume. I'm testing different performance tuning strategies and this idea occurred to me. ...
1
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1answer
187 views

Establishing I/O Patterns for an Application

Are there any system tools that allow you to profile an application's usage of storage? Basically, I'm looking for information on determining whether there are more large sequential reads, tiny ...
0
votes
1answer
577 views

USB Drive Software Disk Mirroring - Is this the right approach?

I have a 1TB NTFS USB Data Drive (no boot, etc...) that I would like to keep a mirror of as a backup in case of hardware failure. It is always connected to my raspberry pi running the raspbian ...
2
votes
1answer
888 views

Best way to encrypt my system on an ssd

I consider to buy an ssd for my laptop (something like Samsung 830 or 840) to make the system more responsive. I want my system (at least my home partition) to be encrypted. However I know about ...
4
votes
4answers
524 views

Grep of many keywords over many files: speeding it up

I am currently facing a "performance problem" while using grep. I am trying to locate the occurrences of many (10,000+) keywords in many (think Linux kernel repository size) files. The objective is to ...
0
votes
1answer
936 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 ...
9
votes
7answers
5k views

Processor usage increases with 4GB RAM installed

I have an Intel Atom D2700 (Synology NAS DS412+) with 4GB RAM running kernel 3.2.30 x86_64. This unit has a single DIMM slot. One thing I, and other's have found, is that when adding a 4GB DIMM ...
2
votes
1answer
1k views

Huge page and performance improvemnt

How can using huge page improve performance? I have read that huge pages improve performance by reducing TLB lookups and reducing the size of the page table. Can someone tell me how this helps with ...
5
votes
2answers
1k views

Is there any performance penalty to having multiple segments for one volume in LVM?

We have a big drive that we've split up using LVM. We allocated one segment to the root filesystem and several other segments to other filesystems. Then we wanted to add more space to the root ...
1
vote
1answer
679 views

Speeding a find rm command with test through parallelization

I want to recursively delete all files in directories and subdirectories with number of lines less than 10, and am currently using the following command find . -type f -name "*.txt" | while read; do ...
1
vote
1answer
727 views

vmstat on virtual machine and large values

Hi I'm using vmstat to track machine performance during some tests (jmeter). This is virtual machine running on a big machine where lots of other virtual machines are installed (about 20 virtual ...
3
votes
1answer
984 views

Measure hard-disk read(), write() speed without caching in QNX 6.5

I am working on QNX 6.5 Operating system. QNX 6.5 supports POSIX APIs. I am trying to build an application which is used to evaluate performance of hard-disks. My application will read/write/read ...
1
vote
1answer
136 views

How to configure Linux to run benchmarks as stable as possible?

I have several long running benchmarks (SPEC CPU 2006 benchmarks) to run on a Linux server. The server is running Gentoo Linux with a Linux Kernel 3.6.11. I saw some big differences between ...
1
vote
2answers
138 views

When all hardware resources are free what would cause linux to run slowly

Sometimes, after a few hours, my system works slowly. I have checked status of these resources: Hard disk using iotop Ram usage using free CPU usage using top None of them are busy. top also shows ...
2
votes
1answer
301 views

Alix Board write performance

I have an alix board on which I have installed debian4alix (sqeeze). After using it for a while I noticed that the write performance of the board was pretty low. I ran the following test: dd ...
1
vote
2answers
768 views

btrfs performance

I decided to mess around with btrfs and found some weird performance anomalies. The tests I've done are with with two external hard drives one formatted with ext4 the other btrfs. ext4 performance ...
2
votes
0answers
582 views

Local disc copy at 10MB/s! What could be the problem?

I am running a Debian 6.0.6 (before you ask). I have a regular desktop computer, nothing fancy... but when I copy a file using nautilus I am getting 10MB/s copy speed and the system is completely ...
2
votes
1answer
1k views

Why is connecting to Oracle Express 11 is very slow on Fedora 17?

I installed oracle-xe-11.2.0-1.0.x86_64.rpm on Fedora 17-64-bit. I was wondering why it is very slow, for example when I want to connect to it using Oracle SQL Developer or JDBC in my web application. ...
5
votes
2answers
1k views

Linux (3.4) SSD swap partition usage causes extreme latency - how to eliminate?

I'm running on 4G RAM with an extra 6G swap partition, SSD is a pretty decent SAMSUNG MZMPA128HMFU model. System responds very well to workloads when things stay in RAM, but as soon as things reach ...
10
votes
2answers
4k views

echo vs <<<, or Useless Use of echo in Bash Award?

By now the Useless Use of cat Award is very well known, and there's also a mention of a Useless Use of echo (not relevant for this question). I'm wondering if there should be a "Useless Use of echo in ...
3
votes
2answers
2k views

Optimal SSD configuration

I am thinking about buying an SSD for my Debian system. However, because I don't know what is the optimal arrangement (i.e. what goes on the SSD), I am not sure what is the optimal size. Obviously I ...
0
votes
1answer
1k views

Rygel slowing down my Debian system

Recently I noticed that a process called rygel is taking a lot of IO resources every time I am starting something on my home system. What is this process doing and how can I disable it?
3
votes
3answers
4k views

Performance virtualbox diskfiles vs rawdisk

Pros and cons with this two ways to make disk for virtual machines on virtualbox $ vboxmanage createhd --format VDI --size ${SIZE} --filename /path/to/disk.vdi and # vboxmanage createrawvmdk ...
2
votes
3answers
4k 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 ...
3
votes
1answer
1k views

Linux disk I/O performance issue — what config options to look at?

We discovered an I/O related performance problem when using the default SLES11 SP2 kernel. Our same application on the same hardware had no issue with (the admittedly ancient SLES9 SP3). We had a ...
3
votes
0answers
1k views

Send print job to printer immediately without queueing, aka increase print performance

I have a ruby/rails web application, one action of which sends PDF files that have been generated by the app to a Xerox 4127 printer on the network. This is accomplished via shelling out and running ...
2
votes
3answers
2k views

Compacting `find` name patterns

I am using find . -name '*.[cCHh][cC]' -exec grep -nHr "$1" {} ';' find . -name '*.[cCHh]' -exec grep -nHr "$1" {} ';' to search for a string in all files ending with .c, .C, .h, .H, .cc and .CC ...
1
vote
1answer
472 views

Does symlinking from Drive A to Drive B affect I/O on Drive A?

I was wondering if IO through a symbolic link affects IO on the host drive even if it points to a seperate drive? My setup is, /dev/sdb2 1.8T 443G 1.3T 26% /home1 /dev/sda3 1.8T 1.7T ...
2
votes
0answers
528 views

Why if I don't disable nm-applet and xfce4-volumed my startup slows down?

I'm running Xubuntu 12.04, and after I ran the update, my login started slowing down big time. I've dabbled a little bit with the programs in Settings -> Settings Manager -> Session and Startup, and ...