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Questions tagged [performance]

The speed at which a program runs

196 questions with no upvoted or accepted answers
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108 views

How to calculate the throughput usage of AWS EBS volume

We have a hadoop cluster running on AWS EC2 instances. Configured 16T st1 volume in datanodes for HDFS usage. We need to understand, what is the maximum throughput hitting on this st1 volumes. Since ...
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2answers
224 views

Is there a way to predict or count the number of page faults?

I am working on hardware performance counter (HPCs) and I seek to use these counters to measure some events accurately. I have found that the non-determinism in hardware performance counter (...
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79 views

Performance of active port - netstat

Below command [root@machine1 output]# netstat -s --udp IcmpMsg: InType0: 371137 InType3: 296 InType8: 386843 InType11: 4 InType13: 141 InType15:...
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1answer
37 views

Is opening new tab equivalent to opening new window?

Is opening new tab in the terminal window is equivalent to opening a new tab in terms of resources? I need to run 16 scripts in parallel. I do not know whether opening tabs or new terminals is the ...
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1answer
81 views

Understanding workload sharing of readwrite in fio

I am exploring fio tools with different options. I want to share the read and write workload, so supplied below jobfile to fio. [read-4K-write-64K] blocksize=4K,64K, rw=readwrite rwmixread=50 size=...
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724 views

Disk io stat “averaged” over a period of time

I am using the iostat utility on my RedHat Linux server to monitor the performance of a disk. When I use "iostat -xd sdh 1", I get the perf result printed every one second. When I use "iostat -xd sdh ...
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296 views

Slow boot when using kernel parameter console=ttyS0 to hide all output

For an end-user friendly operating system, I am creating a basic linux distribution using the Buildroot tool. I am using Syslinux/Isolinux as the bootloader and the Linux 4.14.54 (Long Term Support) ...
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430 views

Measuring block I/O delays using proc FS

I'm trying to measure IO delay due disk access. For this I'm using delayacct_blkio_ticks from /proc/[pid]/stat response. What I'm getting is a constant 0, no matter how much IO is done in my app. The ...
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49 views

how to determine the impact of an running application on system load average due to CPU resource usage?

As of my knowledge Linux system load average is affected by any means that can affect the system like CPU resource usage, memory consumption, disk I/O, network I/O etc. In top command I am checking ...
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1answer
418 views

High IO load by [md0_raid1]

I'm experiencing a 99% IO load caused by [md0_raid1] process every 20-30 seconds. That 99% IO is very short-term, about 1-2 seconds, but it causes lag for other processes due to io wait (it's very ...
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79 views

NC364T nic lots of drop when traffic hit 250kpps rate

I have Server with 32 core CPU and it has NC364T Quad 1G ethernet and i have notice when packet rate hit 250kpps (200,000 packet per second) i start seeing intermediate drops in ifconfig output and in ...
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31 views

systemd service unit that maximizes CPU utilization

How to do I write a systemd service unit that maximizes CPU utilization on a single CPU core? What I have so far = [Unit] Description=Max_CPU_Utilization [Service] ExecStart= [Install] WantedBy=...
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1answer
288 views

Process Id Using ps ax command

I have used: ps ax |grep chrome That gave the following along with other details: 6254 ? SLl 0:01 /opt/google/chrome/chrome 6265 ? S 0:00 /opt/google/chrome/chrome --type=...
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250 views

Comparing I/O schedulers

I intend to compare different three I/O schedulers: "noop", "cfq", and "deadline" and I plan to compare them for both random reads and writes. So far, the only meaningful cases that I have identified ...
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1answer
61 views

Niceness and System showing high CPU in top

We use a VM/server as the jump box to our other servers, it holds all the RSA keys. I keep getting alerts that the CPU is over 75% from VMware. We run 3 bash scripts on there - just general checking ...
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540 views

How to find concurrent number of connections per second with Apache?

A web-server hosting an application for a client ; which is high-volume or transaction server, it is required to find out "number of concurrent connections" currently in use by the server. This is ...
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1answer
115 views

FreeBSD hard drive performance

With FreeBSD 11, the system behaves sluggishly while copying large amounts of files from the system partition to another hard drive. Any time an operation is performed (like opening a terminal) for ...
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509 views

Debian slow after low overnight activity (VS ubuntu)

TL;DR; why Debian becomes slow after long duration low activity but Ubuntu doesn't (and how to fix it)? I've been using Ubuntu for a long time (up to 16.04), recently I changed to Debian (8 for a ...
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73 views

Low performance of a system with higher properties

I tested two systems, both running Linux Mint 18.1 by running the same program on them. System 1 has the following features: Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte ...
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150 views

What is the fastest command to trim the header of a csv file?

I need to trim the header in a csv file. I have used tail -n +2 ... which works fine but it is really slow (I have lots of 100M files), and I don't understand why since no memory is needed from tail ...
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622 views

How to prevent high cpu usage by xorg when using multiple keyboards the same time

I am encountering weird problem when using external usb keyboard connected to my laptop. When I am doing keypresses both on usb keyboard and the one from laptop (i.e. keep pressing ctrl on the first ...
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1answer
716 views

How to convert .bin-files to .iso-files fast?

I try to convert a .bin CD image file (with no .cue-file) of less than 800 MB with iat (Iso9660 Analyzer Tool v0.1.7) to an .iso-file on FreeBSD. With an AMD FX-8370 after 30 minutes iat still has not ...
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1answer
446 views

Running iperf in bidirectional mode goes slower than unidirectional

I used iperf to test throughput on box A and B, both 1Gbps NIC. I found: A->B can reach 940 Mbps B->A can reach 940 Mbps But with iperf -d, to test bidirectional transfers, the result is only about ...
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1answer
132 views

Load average for specific time with all programms

I'm searching for a linux tool to make some "performance tests". I have two (or more versions) of programms wihch do the same. To compare versions with each other I want to run these for a specific ...
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314 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 ...
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2answers
868 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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29 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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1answer
146 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 ...
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1answer
38 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 ...
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353 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 ...
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457 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 ...
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2answers
64 views

does anybody know of a GNU/Linux project which has support for both gcc as well as clang?

Does anybody know of a project (apart from the Linux monolithic kernel) where a/the program can be compiled by both the compilers and can be used to observe their performances, any recommendations ? ...
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1answer
227 views

Wanted: nonassociative array in AWK

I am looking at speeding up some code in AWK by serially processing an internal string representation instead of serially processing an array representation. (For Examples 1 and 2 below assume ...
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283 views

Find system idle time using any system call in microseconds

For the perf analysis and to make decision based on system and app performance I need to find the idle time of system. I want the precise value in microseconds. I know that I can get the value in ...
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1answer
111 views

Calculate the correct MBit/s in my speedtest

I know wget is usually showing the speed in a summary. But in my small OpenWRT shell, I want to test how long it takes to download 100MB with t=$(date +"%s") wget http://speedtest.netcologne.de/...
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2answers
324 views

Analyse high load root cause

This is a cents 5.7 32bit VM running inside a vmware 5.5. host. I see high values of load average with low CPU usage. The VM has 4 vCPU’s and load sometimes reach 20. When I run vmstat I see high ...
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386 views

Isolating some CPU cores reduce average CPU usage of game servers

Hardware: FX8320 (8 cores) @ 4.4GHz, 16GB I run 10 TF2 game servers. Few days ago I isolated some CPU cores with line in linux grub config: isolcpus=5-7 The strange thing - individual CPU cores ...
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761 views

Transmission in idle or slow speed

I am running Transmission on Raspbian via the command line. transmission-daemon is running fine as well as downloading. However after the download is finished and seeding should start, the Raspberry ...
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33 views

centos cluster set core/each_program

I'm using unix server (OS: centos5) and I'm using several clusters. Some clusters have 8 cores, other are 24 cores and etc. I execute jobs using this command. qsub -q cluster_name -d $PWD ...
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1answer
887 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 ...
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1answer
204 views

Powerful Workstation

I heard about ILM's (Industrial Light and Magic) workstations on which they create models and scenes for a lot of different movies. They have workstations with more than 1024 GB of ram and a lot of ...
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38 views

If a buggy application underperforms, it it possible server tuning could have no affect?

To set the stage, imagine if you will: A read-heavy Tomcat Application with MySQL on Red Hat Enterprise Linux with some problematic Java Class files which resulted in the application performing a ...
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1answer
376 views

Performance Issue: AWS Medium Linux Instance V/S Hetzner Dedicated Instance

I am testing an AWS Medium Instance with CentOS (AWS AMI) and comparing it with Hetzner's EX40-SSD (http://www.hetzner.de/hosting/produkte_rootserver/ex40ssd). Software setup on both is comparable( ...
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1answer
233 views

Is my approach to performance testing in Linux environment correct?

I want to do performance testing in a Linux environment for a C++ application. I need to measure the CPU & Memory usage of the application. This application is a multi-threaded application. In ...
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1answer
352 views

udevadm slow boot

After I upgraded from Slackware 13.70 to 14.0, when the machine is booting, it takes it 15 seconds to execute this line: /sbin/udevadm trigger --action=add I understand, that it tries to detect ...
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1answer
100 views

How can I track long-term system performance in Linux (Debian)?

I love the RRD graphs that pfSense provides. Is there a package for Debian or a generic tool that can do the same for my Debian box?