The speed at which a program runs

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2
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3answers
52 views

Remove directories sequentially vs. simultaenously in background [duplicate]

Part of a script I am writing utilizes rm -rf to completely remove two directories. These directories are relatively large and can take a considerable amount of time to remove. Currently the ...
0
votes
0answers
15 views

server load and performance testing

Dears, there are some cluster of servers that are responsible for a telecommunication company databases. the OS's was Linux Redhat installed on bare metal till now, but all the clusters are migrating ...
0
votes
1answer
29 views

HTML5 video performance

I have performance problem with video playing: When I am playing video on youtube, high CPU percentage is used: But when I download the same video and play it in VLC player, CPU usage is reduced ...
1
vote
2answers
16 views

Proper way distribute several scientific experiments across multiple servers?

In case I have 8 powerful machines, what is the proper way to distribute and balance the load from user applications and scientific experiments? Is virtualization right way to go, or is there any ...
2
votes
2answers
45 views

Slow scp transfer speed over wan

I have got a 300mbit symmetrical fiberoptic line, and I have got to transfer a 51MBYTE tar file from HOST A (fiberoptic 300mbit) to HOST B (digitalocean machine with more than gigabit bandwith). On ...
1
vote
2answers
67 views

More efficient X-forwarding?

I open GUI remote programs by SSHing with the -X (or -Y) flag, e.g., $ ssh -Y user@host.com Recently, I found there is a much more efficient way to do this with web browsing only: $ ssh -DNNNN ...
0
votes
0answers
58 views

Debian 8 performance problems with good hardware

I bought about 6 months ago a good laptop (Lenovo ThinkPad E550 : Intel Core i5-5200U, 8 GO DDR3, AMD Radeon R7 M260) and installed Debian Jessie with Gnome 3 (no unity) on it. The system worked fine ...
1
vote
1answer
122 views

Why kernel may be throttled?

My MBR start freezing up for over hour and I've found that my kernel reported being throttled, e.g. (this is just a sample for 2 seconds) $ sudo fs_usage | | grep -i throttled 12:26:45 THROTTLED ...
0
votes
0answers
71 views

Slow USB 3 write speed

Writing to my USB 3 thumb drive (SanDisk Extreme SDCZ80-064G-FFP) is very slow on Linux: 1 GB takes longer than 200s. Using Windows (dual-boot on the same computer), the same 1 GB file can be copied ...
1
vote
3answers
85 views

Is there any way of speeding up this DNS script I made? [closed]

Part of my work is doing a lot of different DNS lookups, so I created a script that displays the information that I need in a neat fashion. Problem is it's not very fast. Doing a bash -x I can see ...
1
vote
0answers
26 views

Performance problem Fedora 23 32-bit @ Dell D630 4GB/Nvidia

I have installed Fedora 23 32-bit at Dell D630 4GB with NVidia Quattro NVS 135M (nvidia.ko, not nouveau.ko). And I have permanent performance problem as X-Windows (Gnome) are very slow and laggy. I ...
1
vote
1answer
31 views

How to obtain counters for swap-in/swap-out on Linux?

I'm trying to obtain counters for swap-in/swap-out activity on CentOS 6. The intention is to feed raw data into RRDtool to generate graphs, and use it to generate alerts. I've had a look at common ...
3
votes
1answer
63 views

What is the overhead of using subshells?

Hopefully this question is not too generic. I am very new to shell scripting and I come from a computer architecture/non-scripting programming background. I have noticed on the scripts at my work that ...
2
votes
1answer
45 views

'cd' complexity on ext4

In order to store attachments, a /path/to/atts/ directory will have numerous child-directories (product IDs) created (from 1 to ~10,000 or maybe more in the future), and in each of this subdir, 1 to ~...
2
votes
1answer
33 views

How does iotop calculate the relative I/O activity?

I am running some heavy I/O processes on my workstation and recently installed iotop to monitor them. Here's a recent screenshot: I'm a bit confused about the readings in the IO> column. It ...
3
votes
0answers
30 views

Is it bad to have thousands of autofs rules?

My company literally has thousands of NFS volumes, which we need to mount on a few of our servers. However, we never mount all of them at the same time; typically we mount about 12 at a time. Most of ...
0
votes
0answers
11 views

Improving MPI performances on a heterogeneous cluster

I am running some parallel programs on a heterogeneous cluster: 2 CentOS virtual nodes (node 1 & node 2) on a Mac host and 2 others (node 3 & node 4) on a PC. When I run a parallel program (...
3
votes
1answer
21 views

Can I deny use of swap space to a specific process (and have it just get killed)?

While developing some software, a program under test sometimes eats all the memory, then proceeds to yomp into the swap space and start thrashing the disk, leading to a predictable drop in ...
1
vote
1answer
39 views

How to monitor system performance over time

I wrote the below script to determine how my system is holding up against various games. It checks all the vitals (GPU, RAM, and CPU) and then appends the data to a log file. Is this a reasonable ...
1
vote
1answer
22 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 ...
13
votes
1answer
189 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
votes
0answers
34 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. ...
3
votes
1answer
64 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
73 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
50 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
55 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
123 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
22 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
vote
0answers
37 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
41 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
147 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
47 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 ...
2
votes
0answers
95 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
229 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) + 2....
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
26 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
71 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
89 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
190 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 /tmp/...
0
votes
2answers
72 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 1.3333e+...
1
vote
3answers
97 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
93 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
152 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
22 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 total,...
3
votes
1answer
87 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
130 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
52 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
73 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: ...