The speed at which a program runs

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13 views

How many interrupts and context switches good for the server?

Munin has chart 'interrupts and context switches on the system'. As far as this is a monitoring tool I assume these values are important for the server performance. So, the question is: how can I ...
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2answers
21 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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15 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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0answers
20 views

Does orca + RICHPse work on Solaris Containers or local zones?

I have just attempted to get RICHPse version 3.4 running on a Solaris version 10 Sun M5000. It seems to run on the global zone but not on the local zones. On the local zones RICHPse just fails ...
0
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1answer
49 views

Will SSD swap improve performance?

I am wondering if i have only 4GB ram and somehow(virtualbox,browser) isn't enough and i cannot proceed to upgrade(due to ultrabook and soldered memory) will swap held in SSD help the overall ...
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1answer
30 views

How does the proc/diskstats work to present that values? And for proc/stat and meminfo?

I am trying to get the diskstats data by same way that the file does. Is there any way to reach that values without reading that file? How the values are placed there? Is there any ".c" file that ...
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0answers
15 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 ...
2
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1answer
41 views

How to track down the source of I/O spikes?

I am using Linux as a desktop, and keep getting seemingly random I/O Spikes. The machine becomes unusably slow. At first I thought it was just that I don't have enough memory. But looking at the ...
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1answer
23 views

Congestion Control algorithm performance testing in FreeBSD

I am working on implementation of a proposed modification of TCP Congestion Control algorithm that would allow to improve it (the CC) by adding a dynamic bandwidth estimation. I have been able (with ...
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2answers
58 views

Make rsync move (not copy) files on local file system

Can I make rsync to move large amount of files instead of copying them when on local filesystem? I would like it to behave like improved mv command. I know about --remove-source-files option but ...
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2answers
83 views

Besides cache, what does the Linux kernel use significant amounts of memory for?

My computer feels really sluggish. According to free, I have only ~200M RAM left and more than a gigabyte had to be swapped out. I know that it is good if memory is used for caching but this looks ...
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0answers
25 views

How to generate graphs from lmbench results?

I need to use the lmbench benchmarking tool to get the system performance statistics. I am able to execute and run the results. In the results folder this is a MakeFile with this information # ...
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38 views

Linux desktop (Mint MATE) requires reboot every few days

Summary After a few days of uptime, my system starts getting slow. How can I determine the cause and fix it? Opening a Youtube video or some web-pages will freeze Firefox for an increasing amount of ...
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1answer
69 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 ...
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0answers
105 views

What is the IPsec bottleneck in Linux?

I am trying to compare the performance of several network security protocols between two hosts connected in Gigabit Ethernet. My goal here is to see if I can saturate my bandwidth, and if not, what ...
2
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0answers
20 views

JVM low-memory tuning

What command-line options would provide the lowest memory-footprint JVM, in OpenJDK, or possibly other JVMs (Linux/Debian)? I'm willing to disable JIT, live with slow or choppy garbage collection, ...
2
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2answers
47 views

Pipe Viewer - Progress monitor performance consequence

I am writing a batch script to sort through gigs and gigs of data. All of the data is text but the script will take a long long time to execute. I would like to give some visual indication that the ...
2
votes
1answer
164 views

Understanding why such a discrepancy in network transfer?

Summary: I can't understand a peculiar discrepancy in network transfer. Why is there such a discrepancy in syncing from one machine to the other and vice versa? Also: Given the maximum network ...
0
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1answer
32 views

Overhead when relocating a directory to a different file system using a symbolic link

I need to relocate some frequently accessed files to a different file system. The simplest way of doing this is to move the directory containing the files to the new file system and creating a ...
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2answers
50 views

How does one determine when a process or machine is IO bound?

I have a node.js process which writes to many different sqlite databases. Sqlite can handle only one concurrent write per database, which is fine since there will be only one write per database at a ...
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0answers
86 views

'nc' using ~100% CPU when transferring a FIFO file

On the server which is always connected I’m using this in a crontab: @reboot nc -k -l 1337 < /tmp/fifo.fifo On the client which is not always on the network or switched on I’m using this ...
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1answer
94 views

how to choose appropriate linux hardware - poor graphics performance

I can't believe I am asking this question here myself. Apologies if this is not the right place for this question. I've been using linux since 1996, SuSE version 4.1... And yet I am still not able ...
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1answer
169 views

Why Linux games are less performanced than Win 7?

I had Windows 7 x64 and now I have Ubuntu 14.04 on notebook HP 4535s. I expected games to be faster in Linux than on Windows because of fewer machine requirements. But it isn't so... E.g., games via ...
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3answers
75 views

Optimise a shell script / command to delete files

I'm running Magento and it doesn't clean up old session data, so I need to clean it up with a shell script / cronjob: 0,30 * * * * /usr/bin/find /var/www/magento/var/session -name 'sess_*' -type f ...
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1answer
26 views

Solaris prstat - definition of “recent” time used in percentages

The man page for prstat (on Solaris 10 in my case) notes that that CPU % output is the "percentage of recent CPU time". I am trying to understand in more depth what "recent" means in this context - is ...
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0answers
115 views

SEGFAULT error 4 in libX11 on another X display caused by War Thunder

I read tons of info about performance boosting for linux gaming. One of them is to run games on a separate X server. After hours of search and tries, I ended up with something "working" for most of ...
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1answer
128 views

Does dm-multipath schedule I/O?

I have a multipath device I'm interested in: [root@xxx dm-7]# multipath -ll mpathf mpathf (3600601609f013300227e5b5b3790e411) dm-7 DGC,VRAID size=3.0T features='1 queue_if_no_path' hwhandler='1 alua' ...
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1answer
81 views

AIX CPU usage - how to know how many CPUs running?

Over AIX 6.1 - I do see the following output, it says I have 16 Max Physical CPUs; but there are only 8 active - why is that? The system will use the remaining 8 if needed? Or are they disabled? # ...
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59 views

Fixing terrible performance when watching/reading video and writing video files to disk

I have had this issue for quite some time and tried many times to fix it on my own and it always fails. IP schedulers, ionice and things like that always yield no result. I even went and bought an ...
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0answers
61 views

Variations in Ubuntu 12.04 /usr/bin/time statistics

I have a command line tool which I run on Ubuntu 12.04.5 LTS. I need to calculate the cpu time for this program. I have been checking /usr/bin/time function. command: /usr/bin/time -v -a -o ...
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2answers
478 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? ...
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0answers
23 views

Using `perf` repeatedly with file input

perf can be used to analyze the performance of a program. Say you want to test the performance of a program prgrm, with input from a file, you can run: perf stat prgrm < inp.dat Now when you ...
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28 views

run netperf without IP address available

I have DPDK set up, with two NICs taken over by DPDK, i.e. the interfaces are not visible to userspace applications. Now, I need to run netperf/iperf to measure throughput performance of port-to-port ...
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0answers
34 views

netperf: run with no control connection

Trying to run netperf without setting up a control connection between netperf and netserver: client% netperf -N -H 10.0.0.2 ... netperf: send_omni: connect_data_socket failed: No route to ...
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2answers
67 views

How to make a filter more efficient

I've created a script to compare a list of users from a MSSQL database against a list of disabled AD users. The tool we use for AD authentication returns data in the following format (with plenty ...
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3answers
129 views

Can I make [ $(($1 % $check)) -ne 0 ]; be more performant and not be killed?

If have the following code which works for up to 13 (line 2) in a few seconds but when I try and do upper teens and 20 it gets killed after a couple of minutes. divisible_by () { for ((check=2; ...
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0answers
168 views

Virtualized Debian Jessie: slow booting / shutting down :(

I have a Debian 8 (Jessie), cat /proc/version says: Linux version 3.16.0-4-amd64 (debian-kernel@lists.debian.org) (gcc version 4.8.3 (Debian 4.8.3-16) ) #1 SMP Debian 3.16.7-ckt2-1 (2014-12-08) ...
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0answers
20 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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0answers
32 views

Little slow downs in Embedded Linux application

My team is working in an embedded Linux solution for a product where a center application receives and process data from the hardware and sends it to a database and to the interface application. In so ...
2
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2answers
84 views

Why is userspace slower than the kernel?

I've heard that FUSE-based filesystems are notoriously slow because they are implemented in a userspace program. What is it about userspace that is slower than the kernel?
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2answers
44 views

How to find the number of bytes rewritten to a folder hierarchy?

I want metrics for how much writing and reading have been done to a folder. vmstat -d gives metrics at the whole disk level. iotop will give per process rw stats. But how can I find out how much ...
0
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1answer
79 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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0answers
32 views

Why does my fresh Debian have a high latency?

The time between clicking and seeing a response is very high. Typing looks very funny, and makes me feel queasy. I think there's about 50-20ms "extra". I would expect a top notch linux distro to have ...
3
votes
1answer
179 views

How does netstat command fit in various layers of TCP/IP model in the performance diagram?

netstat command is useful to, Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. Now, I was reading about the Linux performance ...
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1answer
77 views

Is it useful for a proxy to buffer less data than Linux RCVBUF can?

I am looking at how HTTP proxies and reverse proxies deal with slow client problems. The idea is that the upstream server only have a limited slots for clients and if the client is slow to receive ...
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0answers
320 views

Increasing ulimit stack size benefits?

Hello I'm new in Linux and at my work I have a server that runs a banking software. The company that made the software said that the stack size should be set to unlimited. Does this make the software ...
2
votes
1answer
38 views

Why is my computer sluggish after downloading a lot?

When I download a lot of data (e.g. 3GB) in one go, using a program such as Transmission or Wget, progressively during the downloading, and after it has has finished, the computer always seems ...
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0answers
66 views

How to diagnose CPU performance problems?

Recently I bought a new netbook based on AMD A4-1200 CPU and installed Linux Mint 17 with XFCE. RAM is 4GB So, testing some of my programs, I found very strange behavior. On random intervals, the ...
4
votes
2answers
281 views

Disk busy is close to 100% and iowait is 0,0% on SunOS, how can it be possible?

During monitoring of SunOS5.10 machine I noticed strange behavior: Disk busy is close to 100% Disk waiting time is 0,0% Primary purpose of this machine is running application server on jvm. This ...
17
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3answers
1k views

Why is coreutils sort slower than Python?

I wrote the following script to test the speed of Python's sort functionality: from sys import stdin, stdout lines = list(stdin) lines.sort() stdout.writelines(lines) I then compared this to the ...