The speed at which a program runs

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1answer
38 views

How to deal with high number of page faults?

I've got ~200000 page faults per second and I think it's a huge number and it affects the overall system performance. I'm using MBP with 16G of RAM. How to deal with such number of page faults (...
4
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0answers
19 views

How does ionice work with multiple drives?

I understand how ionice can help you when you have multiple processes requesting access to the same disk resources, but how does it work when you have multiple disks? For example, you have one rsync ...
2
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1answer
24 views

performance comparison of multiple commands excutions

I've got three different programs written in three different languages, and I'm trying to compare their performance in terms of runtime, and memory consumption. What I'm looking for is some command ...
3
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0answers
12 views

Keyboard slowing mouse refresh rate under Debian 8

This odd issue is preventing me from developing software on my current Debian Jessie setup. Whenever I press or hold a key on the keyboard – any key with the apparent exception of shift and alt&...
3
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0answers
58 views

Performance Optimization

I have one script which roughly has to read 1.5 million lines and process the lines and print out output in cvs file. This script is current taking more than 8-9 hours to process 250 thousands lines. ...
0
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1answer
42 views

storage performance test [closed]

So we have some operational Red-hat Linux on physical servers and company are we decided to migrate them to VM's. I wonder if they have same performance on writing and reading from disks. they are ...
1
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1answer
16 views

Responsiveness of a CPU-busy RAM-moderate IO-moderate system [closed]

I am running computationally intensive multi-threaded jobs on my CentOS workstation with 4-core i5. Most of the time all 4 cores are busy, by memory usage is usually 25-50%, so there is no swapping, ...
1
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1answer
26 views

Install Linux to SSD or HDD for virtualizing Windows with QEMU?

In my PC I have 1 TB slow HDD and 120 GB fast SSD. I am curious which one of my drives should be used for Ubuntu installation. I plan to use Windows without dual-boot - by virtualizing it with QEMU (...
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0answers
25 views

HDDs, outer track vs inner track performance benchmarks?

I am interested in relating the position of a file on disk and the I/O R/W performance characteristics associated with this position. I have been able to find two benchmarks, but they are both for ...
1
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2answers
44 views

Poor network performance between AIX 7.1 on 1 Gbit/s and SLES 11 on 10 Gbit/s [closed]

I am having problems with the network performance between SLES and AIX. I have tested the network performance from AIX 1 Gbit/s to AIX 1 Gbit/s SLES 11 10 Gbit/s to SLES 11 10 Gbit/s AIX 1 Gbit/s to ...
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0answers
9 views

Unusual performance of libblas-dev on Unbuntu 14.04

The package libblas-dev in Ubuntu 14.04 seems to have unusual performance (much faster) in some cases in the following question. http://stackoverflow.com/questions/38042451/cblas-gemm-time-dependent-...
2
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3answers
59 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 ...
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0answers
16 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
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1answer
40 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
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2answers
19 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
73 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
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2answers
80 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 ...
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0answers
65 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
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1answer
128 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
1answer
155 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
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3answers
94 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
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0answers
36 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
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1answer
39 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
70 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
47 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
50 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
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0answers
31 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
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0answers
13 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
23 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
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1answer
51 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
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1answer
25 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
202 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
36 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
78 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
74 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
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2answers
62 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 ----- ----------- ------------------------ ------------...
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0answers
62 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
176 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
23 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
51 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
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1answer
44 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
148 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
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2answers
55 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
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0answers
106 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
308 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....
46
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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
31 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
76 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
102 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/...