Questions tagged [performance]

The speed at which a program runs

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6
votes
2answers
5k 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 ...
31
votes
5answers
40k views

How to speed up X over SSH on a slow network connection?

Are there any specific recommendations on speeding up X applications over ssh on a slow network connection? In this specific case, I am accessing a server located in west coast from a laptop in east ...
0
votes
2answers
34 views

Does the “watch” command put stress on a scheduler?

I have an account on a compute cluster which uses the SLURM scheduler. I have some jobs in the queue and I'm using the "watch" command to see their status: watch squeue -u myUserName Does constantly ...
2
votes
1answer
5k 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 I ...
-1
votes
1answer
63 views

Why Linux doesn't reserve some resource for itself? [closed]

As we all know, if a Linux system is running out of memory. It will almost freeze, and we cannot even kill the process to release memory. So I am wondering why the system doesn't reserve some memory ...
3
votes
1answer
43 views

Maximize RAID1 efficiency when using usb 2.0 and usb 3.0 interfaces

I have available a single USB 2.0 port and a single USB 3.0 port and would like to set up two HDDs (both USB 3.0) in RAID1. Not entirely sure how mirroring works, but was wondering if there was some ...
26
votes
8answers
16k views

Make disk/disk copy slower

Is there a method of slowing down the copy process on Linux? I have a big file, say 10GB, and I'd like to copy it to another directory, but I don't want to copy it with full speed. Let's say I'd like ...
0
votes
0answers
31 views

Large file processing performance

I did a simple performance test of csv processing a while ago, and want to share results with community, maybe you can point out, what test could be more precise and fair. Firstly i took out 42 MB ...
2
votes
2answers
111 views

How can I make my sed script run faster?

I got this script my a related question of mine - How do I insert the filename and header to the beginning of a csv find . -name '*.csv' -printf "%f\n" | sed 's/.csv$//' | xargs -I{} sed -i '1s/^/...
0
votes
0answers
12 views

Debian bootchart2

I try to enable bootchart on debian to collect performance metric and build graphics. I follow this guid. The following approaches doesn't work for me: When system reboot press e and append command ...
-1
votes
0answers
43 views

improve dd & tr speed on an Android device/shell

How to improve the speed of this command? tr '\0' '\377' < /dev/zero | dd of=/path/one Note that I'm executing on an android device. I have also tried to achieve the same thing with some scripts, ...
0
votes
1answer
868 views

Where is NMon cron job for AIX?

While trying to know where is NMon job configured to run; I do find that it's NOT listed on Crontab (using crontab -l). BUT - the job is currently running as expected, which is weird. See the ...
1
vote
0answers
11 views

PC slows to a halt after I play more than 1 game of Rocket League

Here are my system specs. System: Host: mohammed-pc Kernel: 5.2.1-1-MANJARO x86_64 bits: 64 compiler: gcc v: 9.1.0 Desktop: i3 4.16.1 info: i3bar dm: LightDM 1.30.0 Distro: Manjaro ...
1
vote
0answers
12 views

Test how many active users can SSH in before experience performance issues [closed]

I have a Kali Linux Rolling virtual machine I've set up on a type 1 hypervisor that I want my students to access via SSH so they can interact with other VMs on my environment. I want to make sure I've ...
1
vote
0answers
271 views

How to diagnose slow upload speeds on Ubuntu Server 18.04

I'm currently running Ubuntu Server 18.04 on a home server build to act as a Plex server, among other things. I have it connected via ethernet (with a 5-port switch between it and the router), and get ...
3
votes
1answer
898 views

dd, ddrescue, dd_rescue performance according to OS (Ubuntu, macOS)

I put this question: recover files from HSF+ USB External HD, test on CentOS 7 to diagnostic And this https://askubuntu.com/questions/955325/using-gpart-testdisk-to-recover-gpt-for-files-from-...
0
votes
0answers
13 views

Rebinding many keys at once

My goal is to have a very accessible way to remap many different keys. More specifically I want the number row and the home row to swap positions on my keyboard when I press shift+space. Right now I ...
0
votes
0answers
6 views

How we can get performance metrics from VTune in command line of Linux?

I am going to record all performance metrics mentioned https://software.intel.com/en-us/vtune-amplifier-help-cpu-metrics-reference by using VTune in command line for my C++ code. I used $ amplxe-cl -...
3
votes
3answers
474 views

Performance of calling POSIX-specified functions versus direct Linux kernel calls

In an answer over on Stack Overflow, I provided a code sample to perform some small task referenced in the question. The original question had to do with the fastest-performing technique (so ...
3
votes
2answers
204 views

Why applications on FreeBSD run slower than on Linux?

Update They don't! At least, not for me. See my answer. Original question According to last year's Phoronix benchmarks, applications on FreeBSD mostly run slower than on Debian (including ...
23
votes
1answer
8k views

How to ensure exclusive CPU availability for a running process?

At first, the question seems to be a little bit silly/confusing as the OS does the job of managing process execution. However, I want to measure how much some processes are CPU/IO-bound and I feel ...
2
votes
1answer
263 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 ...
0
votes
1answer
54 views

Why is Arch GPU performance faster than Debian and Windows?

I have used Linux for a while, recently switching to Arch, and decided to test frame rates in Arch, Debian, and Windows. I first installed Windows (just drivers and Firefox, for I wanted to remove ...
0
votes
0answers
16 views

Can perf events detect deadlock in C++ codes (Linux)?

I am using perf tools to get some performance counters. I would like to know if it is possible to detect deadlock by checking performance counters included in perf events.
2
votes
0answers
29 views

dd measurement question

I am wrestling with some perceived performance issues on a 3-node HPE Apollo cluster running Linux. (The cluster supports a backup application.) These are very $$ servers. In our setup each node ...
0
votes
0answers
27 views

Want to capture host metrics for 60 min in every 3 sec through nmon

I want to run nmon for 60 min which will collect the host metrics in every 3sec. And to achieve this I run the below query on my host, nmon -ft -s 3 -c 60 /home/Documents/nmon When I analyze the ...
0
votes
2answers
68 views

Alternative of too much slow gzip -d command

I'm using an production server for loading large data set to Hadoop to access from Hive table. We are loading subscribers web browsing data of Telecom Sector. We've large number of .csv.gz file (File ...
2
votes
1answer
33 views

How to speed-up programs launch with my ssd?

I have 2 disks on my machine: ssd and hdd. / mount point is on ssd, /home is on hdd. C:/ on my Windows 10 is on ssd, too. It seems to me that some programs (like Chromium web browser) launch much ...
0
votes
3answers
114 views

System performance commands in Linux [closed]

How can I find determine real-time system performance parameters such as memory usage, CPU usage, disk usage from the terminal in Linux. I have asked Google but have not found a succinct suggestion. I ...
0
votes
1answer
69 views

Can I distinguish between swap thrashing and non-swap high IO latency somehow?

My system becomes much, much less responsive, every time I clone a VM image. I'm using virt-manager, and I can see the IO is performed by several qemu-img convert threads. I tried to gather some ...
7
votes
2answers
3k views

Why does my system use more RAM after an hour of usage?

I am using Arch Linux (5.1.8-arch1-1-ARCH) with the XFCE DE and XFWM4 WM. Things are pretty elegant and low on RAM and CPU usage. After the boot, and when the DE is loaded completely, I see 665 MiB ...
2
votes
0answers
42 views

What is the relation between IO wait utilisation and load average

Load average uses processes that are running or runnable or in uninterrupted sleep state. So do the processes in uninterrupted sleep state correspond with the %wa as per the top command? Both are ...
2
votes
3answers
327 views

Display “burps” every 30 seconds

I'm running Mint 18 on a Dell i7 and I have this annoying issue that I can't find where its coming from. Every 30 seconds the display freezes for about 0.5 seconds. The issue is persistent and ...
1
vote
1answer
1k views

Why is my UDP bandwidth significantly lower than TCP bandwidth in iperf

I am running a simple bandwidth test between two VMs using iperf. I am getting very different bandwidth reading for TCP and UDP where the UDP bandwidth is terribly lower than TCP. TCP: root@i-sahmed-...
1
vote
1answer
77 views

Could AIO fsync improve dpkg performance?

Could dpkg, the Debian package manager, gain a noticeable performance improvement by using one of the AIO fsync() operations, instead of sync_file_range() + fsync()? The [proposed] fsync2() API is ...
0
votes
1answer
64 views

Why does rename() take longer when fsync() is called first?

In this test, why does rename() take longer when fsync() is called first? Environment: btrfs, mechanical HDD, Debian 9 container, running on kernel 5.0.17-200.fc29.x86_64. Test command: dpkg -r ...
1
vote
2answers
1k views

Fedora 25 Running Slow After Software Update

I've been running Fedora 25 on my machine for a couple weeks now. I happened to shut down the machine, and there were some software updates that automatically installed. After booting the next time ...
0
votes
0answers
22 views

What are the performance overheads between logging in to another user account via ssh vs login

In Gnu/linux systems, I can perform a full local login (i.e. where logname returns the same output as whoami) by two methods: login: sudo login second_user (prompted for password) ssh: ssh ...
1
vote
0answers
31 views

Slow wired connection on Linux but normal speed on Windows

I installed Ubuntu, Pop_OS, Manjaro, Neon, and Deepin, to my desktop PC (specs at bottom). My internet speed was very slow, basically unusable. Windows gives a normal 15 Mb down and 10 Mb up, but ...
1
vote
1answer
109 views

How to limit frame-rate for all games on Linux?

System Linux Mint 19.1 Cinnamon 64-bit, based on Ubuntu 18.04 LTS. Related Hardware CPU: Intel Core i7-7700HQ (Ark Intel) GPU: NVIDIA GeForce GTX 1060 6GB (Max-Q Design) Screen: 4K laptop 15.6 inch ...
2
votes
2answers
156 views

NVMe disk shows 80% io utilization, partitions show 0% io utilization

I have a CentOS 7 server (kernel 3.10.0-957.12.1.el7.x86_64) with 2 NVMe disks with the following setup: # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT nvme0n1 259:0 0 477G 0 ...
0
votes
0answers
17 views

Huge hdd usage while gaming

For testing I tried to run Path of Exile and Guild Wars 2 on Ubuntu Budgie and Mint XFCE. To run PoE I used steam. To run GW2 I used Lutris. When any game is fully loaded and I do not touch anithing ...
0
votes
2answers
2k views

Write access time slow on RAID1

I'm running MongoDB on my personal computer. I noticed that performance is much slower when the data are on my 2-recent-spinning-hard-drive-software-RAID1 than when they are on an older spinning hard ...
0
votes
1answer
33 views

Performance reduction activating trace-functionality in kernel

Is there any performance reduction to be expected from just activating trace (ftrace) functionality in the Linux kernel, but not using it at run time?
1
vote
1answer
293 views

transmission-daemon: UDP Failed to set receive / send buffer

I just compiled the transmission{-daemon,-cli} on my Debian 10 Buster, and installed it with some minor and major problems. One of those minor ones is apparent failure to set UDP receive buffer / ...
3
votes
1answer
783 views

btrfs balance taking way too long

I have a btrfs RAID1 array (two 891GiB partitions on two HDDs) on my laptop. When I run btrfs balance it takes a huge amount of time to complete. I know if I would like to balance the whole ...
4
votes
1answer
146 views

Case insensitve tab completion zsh without increasing startup time significantly

So I wanted to get away from oh-my-zsh because it made my shell startup lag noticeably (>0.1s). Indeed, after removing oh-my-zsh the startup time went to 0.02s but now I started adding features ...
1
vote
1answer
83 views

Improve performance when using “system” call (shell escape) processing large files in awk

I have an awk script that processes very large files that look something like this: K1353 SF3987.7PD833391.4 KARE K1353 SF3987.2KD832231.4 MEAKE K1332 IF4987.7RP832231.2 LEAOS K1329 SF2787.7KD362619....
4
votes
2answers
2k 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 ...
1
vote
3answers
3k views

CPU > 80% - how can I debug?

I am running a laravel application on a Ubuntu 14.04 digital ocean vps and I am using New Relic to monitor the server. I got an email alert that my CPU usage was above 80%. I logged in to New Relic ...