Questions tagged [multi-threading]

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NVMe parallel writes

I'm trying to understand better how writing to NVMe can be optimized. I have a process which writes a large amount of data to disk (~100 gb) in one batch job. The data is spread across 100s of files. ...
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1 vote
1 answer
56 views

Synchronizing threads in multithreaded applications

I use the SIESTA dft package on a CentOS 8 (core) system with a 16 core, 32 thread XEON processor with OpenMPI version 4.1.1 for all calculations. Since I have 32 threads, I use 28 of them to do a ...
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Strange issue with Pthreads - Why is there a delay in each new Thread Submit when opcache.enable_cli is disabled?

So for context, I am running PHP-FPM 7.4 on Ubuntu and I compiled it with ZTS. Then added the extensions Pthreads and ZSTD . I am running a few hundred tasks and I need them to spawn new php processes ...
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2 votes
2 answers
5k views

Can I have multiple threads running in parallel in a pod with a CPU limit set to 500 millicores?

I have a multi cores Kubernetes cluster, inside it I have multiple pods configured with a CPU limit of 500 millicores: resources: limits: cpu: "500m" It is ...
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1 vote
1 answer
174 views

Laravel/PHP process on debian 10 only ever using one of two CPU threads

I am running a Debian 10 Buster server on a google VM with PHP 7.3 Apache2 and MySQL 8. On the server, I am running Laravel 8 as an API for two clients. I recently upgraded the VM to an n2-standard-2 (...
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19 votes
5 answers
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What is better for a Java Web Application: more CPU cores or a higher clock speed?

I'm not sure whether serverfault is the right place to ask this, but I wonder what choice you would make if you had to select a new CPU type for your Java Web Application: a) a CPU with 32 cores and ...
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  • 369
1 vote
1 answer
688 views

Intermittent KVM performance issues causing performance glitches

We are currently hosted on a hosting provider that allows us to set up multiple virtual machines using KVM, where each virtual machine runs on it's own physical box (ie: one hypervisor, one VM with ...
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4 votes
2 answers
1k views

Why are concurrent downloads faster

Many download managers like this, this and this support downloading a file over multiple parallel connections, one per thread. The concept is that each connection will download one part of the file ...
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5 votes
1 answer
14k views

How can I tell the maximum threads my server can run?

Here is the machine spec: CPU(s): 20 Thread(s) per core: 1 Core(s) per socket: 10 Socket(s): 2 Based on what I've read so far, these numbers mean that I can run 20 ...
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  • 153
1 vote
0 answers
217 views

Worker processes in Celery

I have a CPU intensive Celery task and within one of the task it can be further parallelized using joblib. By default, starting a worker with celery, will create a pool with number of max concurrency ...
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2 votes
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120 views

DNS doesn't resolve some domains on huge amount of requests

I need to check 200kk (200,000,000) domains for availability and CMS information. I'm using php 7.1 and simulating multi-thread check. Hardware and config The server hardware: Multicore CPU, 64GB ...
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2 answers
1k views

Scaling Apache/PHP is as simple as maximizing the number of CPU cores?

I have an Linux/Debian server with Intel i7 CPU with 4 cores and 8 threads. When I run my heavy duty Apache/PHP job it uses 1 thread, and when I run concurrent Apache/PHP jobs they each use their own ...
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2 votes
3 answers
5k views

Copying files using multi threading increases performance - Why?

When copying files from one location to another, the most used resources are memory (buffers) and I/O on the devices. However, when using a multi threaded copy utility such as Robocopy, when you ...
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4 votes
3 answers
3k views

Why having more and faster cores makes my multithreaded software slower?

I am experiencing bizarre behavior on scaling a multiprocess/multithreaded C++ application. The application contains 10 separate processes, communicating through Unix Domain Sockets and each one ...
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0 answers
137 views

Apache 2.4 mpm_winnt: one thread takes all resources

I am working with Apache 2.4.33x64 on Server 2008 to run a site for max. 15 users. On the site you can do some really expensive calculations which can take some minutes (an external script is called). ...
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4 votes
0 answers
2k views

Fastest way to sort very large files preferably with progress

I have a 200GB flat file (one word per line) and I want to sort the file, then remove the duplicates and create one clean final TXT file out of it. I tried sort with --parallel but it ran for 3 days ...
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Memory utilization in Centos OS 6.6 (Virtual and RSS)

My C++11 application run for days without reboot to perform fluid simulation. After running it for 6days, this is the memory footprint: RSS 54MB VSZ 5.6GB Why virtual memory increased to 5.6GB? There ...
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3 votes
0 answers
202 views

Read/Write Split in Mongodb [closed]

We are looking for some load balancing tool which can split read and write load in between replica and master node, I know it can be possible through driver or application level but I would like to do ...
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1 answer
245 views

HAProxy uniform balancing between processes

We using nbproc 10 for multiprocess HAProxy. Server with Intel(R) Xeon(R) CPU E5-1650 v3 @ 3.50GHz. In config: nbproc 10 cpu-map 1 0 cpu-map 2 1 cpu-map 3 2 cpu-map 4 3 cpu-map 5 4 cpu-...
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1 answer
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Can Apache HTTP server work as thread-per-request?

I'm trying to fully understand the differences between Apache and Nginx. I've come across the concepts of thread-per-connection and thread-per-request. Then, I've also learned about Apache's MPMs. ...
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windows server 2012 cpu quota

I have written a multi-threaded program that is running on Windows server 2012. The program will create threads to take advantage of multiple CPUs and I can control the number of simultaneous threads ...
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  • 101
0 votes
2 answers
460 views

run command on multiple threads

I am running a command (pngquant to be precise: https://github.com/pornel/pngquant) in a terminal window. I noticed, that if I open 4 terminal windows, and run pngquant command in each of them, I get ...
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  • 113
0 votes
1 answer
432 views

Syslog-NG is spooling messages

I am currently using Balabit's Syslog-NG to concentrate my IT logs and convey them in a remote server, via a TCP connection, which can allow one listening port only. Thing is, my log volume is really ...
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  • 498
0 votes
1 answer
722 views

Virtual machines and dual socket setups: minimizing need for CPU-to-CPU communication

I am planning to build a multi-OS workstation overseen by (probably) KVM, on which I will do a variety of tasks. Some of these tasks lend themselves to multithreading better than others, so I want to ...
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1 vote
1 answer
63 views

Application caps at 20% utilization per core no matter how many threads are launched

I'm trying to use a Dell Poweredge R900 I got secondhand as a compute pool (4x quadcores gives me 16 cores to run simulations with). It's running windows server 2008 R2 enterprise at the moment. I'...
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2 votes
0 answers
44 views

How does a server (e.g. web) manage multiple request/connections? [closed]

I read that apache has a solution to create new thread per new request, but I still have some questions. How is possible that one server can manage thousands (even a milion connection - depends from ...
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-2 votes
1 answer
223 views

PHP - Multicore for hashing

I have a server with 2 intel xeons on it, this gives me quite a lot of cores. And on that server i have an app, that uses php to hash passwords in blowfish. But the issue is php is not using all the ...
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0 votes
1 answer
2k views

Why robocopy with multi-treading copies faster

I have been using robocopy with the switch MT and really makes a difference in coping time. I would like to know why the CPU treads act as a bottle-neck while copying files or what makes robocopy ...
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2 votes
0 answers
572 views

Is there a way to check resource utilization on a cluster running SLURM?

Not sure if this question fits better here or at Unix.SE but I figured it feels more appropriate here. I am running some computation-heavy research on a national cluster which uses SLURM for ...
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0 votes
1 answer
205 views

Application GUI on a heavy load tomcat doesn't respond

We have a backend webapp installed on tomcat 8 that has a GUI part written in Apache wicket MVC (version 1.4) - the wicket GUI fails to respond the moment the server starts doing heavy processing. ...
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1 vote
3 answers
1k views

Why is method that uses gevent in a mod_wsgi deployed Flask api raising error about switching threads?

I am trying to deploy a Flask api via Apache/mod_wsgi. The api uses Gevent to provide concurrency for a recursive method. However, it is throwing the following error [Mon Feb 08 12:05:37 2016] [error]...
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2 votes
2 answers
4k views

The apache2handler SAPI is not supported by pthreads

It has been weeks now that I cannot install pthreads. I am going to list the error logs then I will list my configuration options. These are the errors I get:(Apache Error Log) The apache2handler ...
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1 vote
1 answer
609 views

Use GPU to speed up server processing

I have a server that handles strings of data pushed from another server. Sometimes we receive thousands a second. This might be overly simplistic but would putting a Graphics card in the server assist ...
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0 votes
0 answers
131 views

App not using all cores on VM after migrating host

We have a DL380 G7 with 2x Xeon E5645 processors running at 2.4Ghz, on which we had ESXi 4.1 installed with a few VMs. One of our VMs had Windows Server 2008 R2, with 4x vCPU and 12GB RAM. This was ...
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3 votes
1 answer
709 views

multithreading a single threaded application worker [closed]

I have a server which I want to dedicate for converting doc files to pdf via LibreOffice. The server has 6 cores and LibreOffice is single threaded. This means that generating a single pdf uses 16.666%...
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2 answers
905 views

how to check if a process with heavy io usage is running properly

I am now managing a computer cluster for scientific computing. Some processes in the cluster need heavy io usage. Now I find such a process: Its state changes rapidly between DOWN and RUN and its cpu ...
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-1 votes
2 answers
1k views

How to run a single-threaded application on multiple processor cores efficiently? [closed]

There is this old application that we are using (called Aldfaer) that only uses a single thread. One of its processes takes about 90 minutes to complete at this moment, and we would like to decrease ...
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0 votes
1 answer
409 views

Install amphp / thread on a Debian Wheezy 64 bits

I'm trying to install a multi-thread PHP system on one of my server. After a few readings, the simplest solution seems to use Pthreads with an amphp\thread implementation. http://www.mullie.eu/...
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1 vote
1 answer
2k views

uWSGI raises segfaults when defining several mount points in preforking+threaded mode

I'm hosting an application consisting of several Python modules. So far we use Apache in MPM worker mode and mod_wsgi, which is a working environment. Now we want to check if nginx + uwsgi may be a ...
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16 votes
1 answer
12k views

Taskset not working over a range of cores in isolcpus

To preface I'm using Debian Wheezy with kernel 3.2 on an AMD64 chipset. My machine has two Xeon E5-2690 cores. I set up the boot parameters so that all the cores on one CPU are dedicated to a single ...
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13 votes
1 answer
6k views

Why do we get a sudden spike in response times?

We have an API that is implemented using ServiceStack which is hosted in IIS. While performing load testing of the API we discovered that the response times are good but that they deteriorate rapidly ...
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-2 votes
1 answer
1k views

Check if mysql is using multithreading?

When I check the processes/active tasks on centos using the top command, when using SSH. I only see 1 mysql process. Does this mean that it is only using one cpu core out of my 4 cpu cores?
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2 votes
1 answer
4k views

Django mutli-threading on apache/mod_wsgi/windows

I am quite new to the combination of apache and django and quite naive frankly regarding to how multi-threading is handeled. Specifically I run on a windows server, so I know the MPM is only thread-...
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2 votes
2 answers
160 views

Linux: Finding the system processes which are at the top

I am running a multithreaded program on my 8-core processor. top command shows 8 processes are running and each one utilizes a core by 100%. The problem is that only 21% are marked as user cpu and my ...
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1 vote
2 answers
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redmine multitheaded

Our redmine server is not responding due to connecting it to a large repository. It has not crashed but it's just busy until it checks it out, or whatever redmine does when you set a new repo for a ...
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3 votes
1 answer
1k views

How does Apache process several requests at a time?

If 10 requests hit Apache, does it process them one by one, so when R3 finishes, then it starts to run R4, or does it fire 10 processes/threads/whatever and are resolved simultaneously? Now some ...
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2 votes
1 answer
596 views

Python multithreading not working on VPS server

I am running an python multithreaded application with multiple processes which scrapes data from some websites. While running on my localhost It works great, but on the vps server I am using( Centos 5....
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0 votes
1 answer
4k views

Single-threaded application being balanced across CPU cores?

Is there an easy way to check whether a certain single-threaded application is being balanced across CPU cores by Windows? I have already tried Process Explorer but I could not find a way to read it ...
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  • 461
1 vote
1 answer
410 views

Confusion about PHP Non-Thread safe

PHP 5.1.6 - Non-Thread Safe ( Thread Safety=disabled in phpinfo() ) Apache 2.2.3 - MPM prefork Should I be using prefork or worker? If so is this an easy switch?
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  • 207
1 vote
2 answers
1k views

PHP / SSH2 Multi-threading

I'm basically done using SSH2 with PHP. Some may already that while using it, the PHP code actually waits for all the listed commands to be executed in SSH and when everything is done, it then gives ...
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