The speed at which a program runs

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-3
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0answers
14 views

how can I address the root cause of the high “in” and “cs” at the vmstat output

root@wis-virtual-machine:~# vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st ...
3
votes
1answer
41 views

How can I repeatedly send the contents of a file via socat / ncat to a socket

I'm running some performance testing, and I'm trying to send the same file repeatedly to a socket. If I do something like: $ socat -b1048576 -u OPEN:/dev/zero TCP4-LISTEN:9899,reuseaddr,fork $ ...
2
votes
2answers
65 views

What is the best way to setup 3 HDDs with 3 OS on one computer?

I am building a new PC, I am a developer of whatever people want me to make, but I personally like to code games. To do this, I have a simple set of requirements: Machine must run Windows 7, to run ...
0
votes
2answers
35 views

Can someone please explain the relation of CPU bottleneck on AIX regarding lcpu and r?

# vmstat 60 2 System configuration: lcpu=12 mem=46080MB ent=1.10 kthr memory page faults cpu ----- ----------- ------------------------ ...
1
vote
0answers
34 views

Why my server cannot serve more than 400 concurrent connections

I have an Ubuntu 14.04 LTS, kernel 3.13 in a Intel Xeon + 8Gb box. It has apache 2.4.7 configured in mpm worker with up to 4000 workers. The max bandwidth allowed by the ISP is 100Mbps. If I test ...
1
vote
1answer
40 views

UDP receive buffer error

We are running opensips SIP proxy in high traffic environment, it's using UDP protocol. We are seeing sometime RX error or overrun error on interface. I have set rmem_max to 16M but still i am seeing ...
0
votes
0answers
21 views

Ubuntu trusty format disk slower than RHEL7?

I observed that disk formatting is much slower in Ubuntu than in RHEL7. Does anybody know why that is? EDIT: Forgot to mention, I'm formatting the disk with ext4. Using mke2fs
1
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0answers
23 views

Configure xterm to use ctrl+shift+c/ctrl+shift+v for copy/paste?

I was using terminator for my terminal emulator, but I'm seeing huge performance issues with it. ie, launching a new terminal session takes 20-30 seconds on my netbook. gnome-terminal is better, but ...
1
vote
1answer
36 views

Fast filesystem for virtual backup environments

I know filesystem supporters war is behind the corner and there are plenty of fine tuning guide for each filesystem in the wild, so please stick to the specifications: I'm asking what would you ...
1
vote
1answer
145 views

Seq performance hit when specifying a format string

Running seq (GNU coreutils 8.21) without specifying a format string runs extremely quickly compared with any possible format I tried: $ time seq 1e8 > /dev/null seq 1e8 > /dev/null 0.68s ...
1
vote
2answers
30 views

Tracking/Monitoring Short-Lived CPU-Intensive Process on one CPU

So I've been working with this issue for some time now, and I'm having trouble finding the tools to troubleshoot this problem, which I have to imagine exist. So here's the basics of my problem: We ...
3
votes
0answers
59 views

ZFS (on linux) performance issues

I have a server setup with RaidZ2 (8 disks in array) + 2 spares (+ system disk). The disks are 6TB each, 7200 RPM SAS The machine runs Centos7 x86_64 (not a VM), and has 128 GB of RAM and 48 cores ...
4
votes
2answers
133 views

Why is boot slow?

I'm using Fedora 23, MATE edition. The computer feels slow to boot. How can I speed it up? Full details http://i.imgur.com/vrLGXDp.jpg $ systemd-analyze Startup finished in 16.571s (firmware) + ...
45
votes
2answers
4k views

Why is egrep [wW][oO][rR][dD] faster than grep -i word?

I've been using grep -i more often and I found out that it is slower than its egrep equivalent, where I match against the upper or lower case of each letter: $ time grep -iq "thats" testfile real ...
0
votes
1answer
25 views

Does RAID 0 have a performance gain even on a low resource OS like Ubuntu or Mint?

I have Windows 10 installed on raid 0 right now but I was thinking about wiping it and installing mint. I already have an i7 3770, 24gb ram and a 250gb ssd. Would there be any improvement by ...
3
votes
1answer
67 views

VAR=`cat file` and then repeating echo “$VAR” is slower than repeating cat file. Why?

There are about 10.000 files in files/ and 10.000 lines in metadata.csv. Where metadata.csv contains information about the files. I have a shell script which prints information about each file and ...
0
votes
2answers
52 views

command to list logical volume I/O statistics on AIX

I am looking for a command which displays the I/O statistics of logical volumes (like reads/sec , writes/sec, io utilization %, read kb per second, written kb per second) . I tried iostat, but its ...
4
votes
3answers
184 views

How to search efficiently for a list of strings in a big code directory

I have a list of strings, for every of those strings, I want to check if it occurs in a big source code directory. I came to a GNU grep solution that gives me what I want: for key in $(cat ...
0
votes
2answers
53 views

Memory usage and space disk on Solaris 11

How can I monitor Memory Usage: 33/512MB (6%) Disk usage: 4.2/20GB (23%) CPU Load: 0.01 on a Solaris 11 System? I want to make a script to monitor my desktop resources.
1
vote
2answers
33 views

Effective way of changing the format of numeric file data

So I have a big file containing the values of a matrix with the folowing format: (0,0) 0.6666 (0,1) 0.0000 (0,2) 1.3333 ... And I want to convert it to: 0 0 0.6666e+00 0 1 0.0000e+00 0 2 ...
1
vote
3answers
61 views

How to configure swappiness in Linux Memory Management?

The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk,what is the default setting and how to configure that to improve overall ...
0
votes
1answer
51 views

Will LVM partitioning affect my SSD life or performance?

I've installed new system (Linux Mint 17.3, laptop) using LVM partitioning because I currently don't need a swap (there is enough RAM - 12GB) and I want to use my SSD (Samsung 850 evo 250GB) more ...
0
votes
1answer
58 views

Lots of TIME_WAIT in netstat on apache server

What would be the reason for many TIME_WAIT here? Even we have very few ESTABLISHED, SYN connection. [root@www ~]# netstat -natp | grep "210.XX.XX.XX:80" | awk '{print $6}' | sort | uniq -c 1 ...
0
votes
0answers
17 views

How to I get dstat to report totals for each minute?

I recently discovered dstat but I am surprised that it seems that when it gives reports for another time interval it does not measure the totals for them. Have a look root@zeus:~# dstat -tdD ...
2
votes
1answer
63 views

If tmpfs has bigger size than your RAM, how much RAM does it use? Are applications privileged for RAM?

If the size configured for tmpfs is bigger than the size of RAM, and there is a lot of stuff stored there in the tmpfs, how is the amount of RAM available to applications determined? If applications ...
0
votes
0answers
89 views

Nginx Performance Monitoring: How to collect CPU, Memory and Disk Utilization data?

I'm relatively new to shell programming and I need to collect statistical data on nginx web server performance running on Linux VMs for further analysis. I have checked some tools and I find dstat ...
3
votes
2answers
38 views

Piped commands performance in embedded Linux

Recently, we purchased a software solution to integrate into a device we're developing. There's plenty we need to modify and adapt to our needs, so today I was going through part of the code to see ...
1
vote
0answers
53 views

Process stuck in kernel code, what is it doing? [closed]

I have a process (db_add) which is stuck is kernel code. This process is the only ressource-intensive process running on the machine. Top reports a 100% (ie it fully uses a single core) CPU usage: ...
3
votes
1answer
72 views

performance regarding “find” arguments' orders

I'm curious whether there are some distinguishing performance differences with different filtering orders when using GNU find. For example, I hope to search all directories in current path whose ...
0
votes
1answer
97 views

How do you make apt-get install faster? [closed]

I just installed Debian for the first time in a virtual-machine (I have used centos/RHEL/fedora for the last 11 years so I have some Linux experience). I did an apt-get install gcc... the command took ...
1
vote
1answer
49 views

Read ahead setting on Solaris

How to get the current read ahead setting on Solaris? On Linux it can be retrieved like this: # echo $(($(blockdev --getra /dev/sda)*512/1024)) (Assuming that blockdev always returns the read-head ...
0
votes
2answers
61 views

Resource usage (% CPU) for given command on OS X

The time -v command outputs % CPU utilization for a given command on Linux. How do I do this on OS X? The Linux/OS X difference is illustrated here. I would like to measure multi-core utilization ...
1
vote
0answers
153 views

RHEL 7 Still CPU Frequency Scaling

When machine is imaged with: RHEL6.x CPU speeds report full 3.3Ghz speed for all CPUs cpupowerutils is not installed RHEL7.x CPU speeds vary (shown in example below) cpupowerutils is installed ...
0
votes
1answer
17 views

Restore boot parameters to default value Linux

I feel my system is getting slower and slower. I am using Ubuntu and my machine is HP ProBook 450 i7 4x2.0GHz, 8GB RAM and an optical HD. Still it takes ~2 minutes to boot, which in my opinion is way ...
1
vote
1answer
37 views

Characterizing iptables impact

Circumstances force us to open a port to the internet and we want to set up a "white list" of IP ranges that are allowed to access that port. I have prototyped the solution so I understand the ...
0
votes
1answer
84 views

string fill performance in shell scripts: what is the best amount and for what shell?

I was trying to determine the best performance for string fill like in: str+="A" #one per loop I came with this script for bash: #!/bin/bash bReport=false nLimit=${1-3000}; #up to 25000 echo ...
0
votes
0answers
42 views

How can I prevent my browser from hogging all system resources?

I'm using a laptop, with a reasonable (though not stellar) CPU and memory. I run Lubuntu 15.10 on it, to be resource-conservative. Still, when I have a browser - specifically, Mozilla Firefox, but I'm ...
0
votes
0answers
36 views

LVM Logical Volume (linear) best performance

As a system administrator, one thing I do very often is increase LV's size. In most cases I have to extend first the VG, adding a new disk (we are talking about virtual machines). I have got a lot of ...
0
votes
1answer
42 views

sed: multiple ranges between patterns, with one pass

I have a script that reads a file of about 3GB and sends it through a pipeline involving a very small number of replacements in a very small part of the file. To accomplish this with minimal overhead, ...
1
vote
0answers
95 views

Reducing Number of MariaDB/MySQL Threads

So I'm running a MariaDB 10 database on a single core server; not super powerful, but then my needs aren't huge either. However, one thing I've noticed is that if I look in htop I have around 28 ...
2
votes
1answer
267 views

Check if partitions are aligned properly for performance?

I just created a GPT disk label for the entire space on my hard disk (/dev/sda) like so: # parted (parted) select /dev/sda (parted) mklabel gpt Warning: The existing disk label on /dev/sda will be ...
0
votes
2answers
28 views

How to find out contention

I'm looking for an easy tool, to graphically show the amount of resources being used realtime. Something like htop but with disk IO, memory and network usage as well. I tried ganglia and the fact ...
1
vote
0answers
18 views

What can interrupt execution of threads which are pinned to cores?

I do low-latency application development and I use isocpu and set thread affinity to reduce (eliminate?) context switching during my critical threads. However, I am unsure what other types of ...
1
vote
0answers
93 views

Debugging Slow Queries in MariaDB/MySQL

I've set up a MariaDB server and everything is running well, with most queries executing in well under 20 milliseconds, but every so often a query will take half a second or longer (sometimes several ...
0
votes
0answers
43 views

spstack, ptrace stopped a process

My server is busy with sys CPU, so I used pstrace to trace it but no output, so I cancel the command inside putty, and then use pstack to trace it again, but no result return either and I closed the ...
0
votes
2answers
67 views

how to delete larger file (e.g., 180G) in unix system?

Because of some reasons, my server machines had some too-large files (e.g.,:180G), How can I delete these files quickly?
0
votes
0answers
60 views

Linux huge IOPS difference - same disks

I've been investigating for some time regarding some IOPS issues I've been experiencing.. And my mind is getting crazy! I have two servers (one bought 2 weeks ago, another 1.5 years ago) that I ...
2
votes
0answers
42 views

Is “top” accounting for Kernel Interrupts?

I have a simple interrupt that is triggered by a GPIO-input. The IRQ only increments a variable and returns. When I turn the frequency of the interrupts up to somewhere around 10-20 kHz, the system ...
1
vote
2answers
261 views

How to call bash function from within awk?

This is a bit tricky; I'm trying to work out the best approach to this problem. I have a couple of approaches, but they seem really hacky and I'd like something a little more elegant. I want to ...
0
votes
1answer
24 views

How can I improve performance using a system remotely via SSH?

I know I can use compression with the flag -C. Any other ideas? Also, besides my internet connection (which I think is fairly fast), what could be causing the network to slow down?