The performance tag has no wiki summary.
3
votes
2answers
63 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 ...
3
votes
2answers
139 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 ...
3
votes
1answer
45 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 ...
1
vote
2answers
71 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 ...
2
votes
1answer
78 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
31 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
54 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 ...
4
votes
1answer
72 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
vote
1answer
50 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
36 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
133 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 ...
2
votes
4answers
110 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
0answers
109 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 ...
6
votes
5answers
330 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
147 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 ...
3
votes
2answers
136 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
72 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
102 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
233 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
78 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
79 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
98 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 ...
0
votes
2answers
253 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
159 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
123 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.
...
4
votes
2answers
303 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 ...
6
votes
1answer
239 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
601 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
169 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?
2
votes
2answers
412 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 ...
0
votes
1answer
327 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 ...
2
votes
1answer
398 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 ...
2
votes
0answers
294 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 ...
1
vote
1answer
82 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 ...
0
votes
2answers
106 views
Is it against linux ethos to provide a progress indicator for running commands? [duplicate]
Possible Duplicate:
Why doesn't cp have a progress bar like wget?
Lately I have been dealing with rather large files in Linux. I often use commands like sed, cut, sort, uniq, awk, and ...
4
votes
2answers
479 views
Does the filesystem influence flash drive speed?
I'm currently filling up an empty 16GB flash drive which gives me a lot of time for imponderables. It's formatted as fat32 or whatever it came with (and I'll probably leave it that way for ease of ...
2
votes
1answer
113 views
Book or online article on analysis and tuning Linux system performance
I am looking for a good book or online article on analysis and tuning Linux system performance.
So far I've found openSUSE 12.2 System Analysis and Tuning Guide which looks promising. Any other ...
4
votes
1answer
142 views
Linux mutex spins [closed]
On Solaris I can use mpstat to see the smtx (i.e., spins on mutex or in other words locks not acquired on the first try) value. This value increasing indicates that swap is being hit too frequently ...
5
votes
1answer
767 views
Fast elimination of duplicate lines across multiple files
I have a huge amount of data in which each (data-)line should be unique.
There are a lot of files in one folder in which this is already true. It is about 15GB splitted into roughly 170 files with ...
2
votes
1answer
69 views
Read only new parts of a file?
I have a large CSV file, that grows by some entries every day (created by an external software which writes always to this one file, no splitting possible). For performance reasons and further ...
5
votes
1answer
757 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 ...
2
votes
1answer
105 views
How to have find only search for files in changed directories?
Currently I'm repeatedly doing a 'find' that's too slow. I'm searching for non-hidden executable files within "$root", excluding "$root/bin":
find "$root" -type f -perm -o+x -not -path "$root/bin/*" ...
4
votes
2answers
245 views
Replace require statements by autoload in .emacs file to improve performance
According to these posts:
How can I make emacs start-up faster
a-nickels-worth.blogspot.de/effective emacs
one can somehow replace require and load statements in the .emacs file to speed up the ...
3
votes
1answer
125 views
Tweak gimp for performance
I just realized that I can start gimp (version 2.8) via
gimp -d
to reduce startup time on an old system.
Are there other tweaks to speed up the startup time of gimp and reduce memory usage?
2
votes
1answer
367 views
What could cause a NAS mount to respond slowly?
I've a directory on a NAS mount (from NetApp), that contains ~6300 image files, total size of this directory is ~ 300 MB. I get two different performances of time ls:
First time (or after waiting 5-7 ...
5
votes
1answer
415 views
What keeps one side of an rsync so busy?
I've got a debian machine in my lan serving as a backup server for the others. It has four HDDs combined into a software RAID 5 md device, on that an lvm, and on that a btrfs. Backups are made using ...
7
votes
1answer
945 views
Why is ping so slow?
My setup:
Server in the cellar + GBit switch. Long cable to the roof. GBit switch. I have three computers in the roof. One has only 100MBit ethernet, one laptop with GBit and a new computer.
Ping ...
6
votes
2answers
247 views
Does the position of partition on disk affect speed?
If I put /var as first partition, then /home and /, will the partition for /var have better performance than if I put other partitions close to head of the disk? Will the disk sector position matter?
...
2
votes
1answer
133 views
How to find what's hogging what resources? [closed]
I've found lots of similar questions, but nothing that's exactly right.
I'm trying to figure out what's making one server run slower than another. I'm hoping for something that would say something ...
4
votes
2answers
483 views
Linux running slow with 0 swap left
Our Linux server is responding very slowly. top doesn't show any excessive CPU usage. I noticed that even though there's about 5GB of free memory, the system is using all of swap with no free swap ...
