The speed at which a program runs

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57 views

What's MINIX 3 performance like? [on hold]

Every time I read about MINIX 3, it seems like it's the future of computing. However, whereas other similar technologies that promise the nine nines -- namely, Erlang -- actually do deliver, and, ...
1
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1answer
14 views

What are the pros and cons of badblock's two non-destructive tests?

I use badblocks to test my 32GB class-10 microSD card that I use to boot my RPi. I already have a functioning file system on it, so I don't want to scan it with the -w option (destructive read-write ...
12
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1answer
106 views

Why does `find . -type f` take longer than `find .`?

It seems like find would have to check whether a given path corresponds to a file or directory anyway in order to recursively walk the contents of directories. Here's some motivation and what I've ...
2
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0answers
17 views

Benchmarking under SELinux Sandbox with Phoronix Test Suite

I would like to run the Phoronix Test Suite 6.2.2 under the SELinux sandbox on Fedora 23, but I can't execute it using $ sandbox ./phoronix-test-suite. I probably don't have the correct SELinux type. ...
0
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2answers
36 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 ----- ----------- ------------------------ ...
2
votes
2answers
66 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 ...
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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
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1answer
42 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 $ ...
0
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1answer
870 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 ...
1
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1answer
37 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
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0answers
38 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 ...
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2answers
2k views

Massive, unpredictable I/O performance drop in Linux

I'm using Debian testing without any problems for ~6 years (I'm just regularly updating it), but recently it started to show a random behaviour that can be summarized as "Low I/O performance which ...
1
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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
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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
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0answers
25 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 ...
0
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1answer
2k views

Physical and logical extents size

I have created a partition with 36TB (/dev/sdb1) in rhel 6.6 Now I want use this for lvm What is recommended size for Physical Extents, Volume Extents and Logical Extents How important PE, VE and LE ...
6
votes
1answer
2k 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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4answers
3k 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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2answers
31 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 ...
1
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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 ...
2
votes
3answers
1k views

Is cmp faster than diff -q?

In a recent Ask Ubuntu question on checking whether some files have differing content, I saw a comment stating that, if the differing sections didn't matter, cmp would be faster than diff. This Stack ...
22
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11answers
13k views

Lightest way to run GUI applications in Linux? [closed]

I realized I can use a window manager without a desktop environment and don't lose any functionality I care about. Applications still work fine, I can still arrange application windows as I please. ...
4
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2answers
136 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) + ...
5
votes
2answers
811 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 ...
3
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0answers
61 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 ...
7
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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 ...
45
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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
55 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
185 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
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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.
10
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2answers
18k views

rsync is very slow (factor 8 to 10) compared to cp on copying files from nfs-share to local dir

I have a freshly installed Ubuntu-server which is ought to be the new backup-server for our VM-storage. The server has 4 nics, 2 of them 10Gbit (in fact an intel x540-T2 with the newest driver ...
1
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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 ...
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3answers
67 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 ...
5
votes
3answers
649 views

On a Linux system, see how busy is file system

I want to know of a command that will show me how (currently) busy is the file system. I'm assuming there exists such a command that will show me this. With such command, are there specific arguments ...
3
votes
2answers
6k 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? ...
2
votes
1answer
64 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 ...
10
votes
3answers
5k views

Why is rm slow?

I have been trying to use rsnapshot for making backups, but I'm finding it unusable. While it is able to diff a directory (50gb) and duplicate it (hardlinking every file) in a few minutes, and I can ...
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
60 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 ...
12
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3answers
2k views

How to average time commands?

I am timeing some of my commands. Now to average the measures, I'd like to run and time my commands a specified number of times, and get the results with a calculated mean and standard deviation. The ...
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 ...
0
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0answers
90 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 ...
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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: ...
23
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6answers
14k views

Is there a parallel file archiver (like tar)?

Is there something out there for parallel archiving of files? Tar is great, but I don't use tape archives, and it's more important to me that the archiving happens quickly (with compression like ...
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
98 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 ...
0
votes
2answers
65 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 ...