Questions tagged [high-performance]

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Server performance jitter after reboot

We are experiencing a strange linux server performance jitter problem: one of our app's P999 curves show that there exist severe jitter on some of our linux servers, while other linux servers don't ...
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0answers
34 views

How can I display graphics on the screen from the kernel over the top of my X11/Wayland session?

I want to draw simple (2D bitmapped) graphics onto my screen (in response to (simple) external inputs) with the lowest latency possible (the order of tens of milliseconds) so I can empirically test ...
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11 views

xeon processors hangs when using even half cores

We have an HPC system with 32 cores zeon processor and about 100 Gb RAM. The problem is that the system hangs or works very slowly even with using 16 cores and half RAM. Its OS is ubuntu 16.04 LTS. ...
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1answer
33 views

Live changing bjobs output

When using LSF command bjobs, I would like to get instantly changing output if I submit another job, because I feel stressful to run the same command again and again. I would like something like top ...
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20 views

PBS Pro Stop waiting jobs for execution

I want to out some of the nodes for maintenance but I have a confusion if I run "qstop @server" will it affect the running jobs ??? My focus to stop only queued jobs those are waiting for free ...
1
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1answer
23 views

Is LSF queue allowed to preempt itself?

I have an LSF queue, say it's queue A. I only want higher priority jobs in queue A to preempt lower priority jobs in queue A, but not jobs in any other queues. If I set queue A to be preemptable, ...
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0answers
77 views

Linux (kernel 3.x and 4.x) Pthread and general process scheduling algorithms

I was wondering if both scheduling (contention) scopes (SYSTEM and PROCESS) are used in the Linux kernel scheduling logic. POSIX supports PROCESS scope pthreads (MXN model) and SYSTEM scope pthreads (...
2
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3answers
5k views

Linux: how to know which processes are pinned to which core?

Is there a way to know which cores currently have a process pinned to them? Even processes ran by other users should be listed in the output. Or, is it possible to try pinning a process to a core ...
0
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1answer
217 views

Lustre and HPC configuration

I have an HPC cluster with 22 nodes, and one head node as a master running Rocks Cluster OS (which is based on CentOS). The nodes and master communicate with private network (10.10.0.0/16). And we ...
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0answers
99 views

high performance computing cluster setup

In my lab, we have several servers used for the simulation programs, but they worked independently. Now I want to combine them to become a cluster using MPICH to make them communicate. But there ...
2
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1answer
75 views

Is the coordination overhead between two processes significant?

I have 24 compute intensive processes, each process running in a single thread, each running about 2 hours. I'm on a 8 core CPU. Does it make a difference on the total run time, if I run all 24 ...
4
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1answer
861 views

Do I need to explicitly enable jumbo frames in NFSv4?

I'm using NFS to share data between VMs. I've already set up working jumbo frames between VMs and host. My question is - do I need to somehow explicitly tell nfs to use jumbo frames or it'll just ...
2
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1answer
154 views

PBS code for submitting a job on the cluster

I'm trying to write a code to submit a job on the cluster, and am using someone else's previous code as a template; is there any way someone could explain each line step by step to me? I think I ...
4
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1answer
920 views

SoftIRQs and Fast Packet Processing on Linux network

I have been reading about performance tuning of Linux to get the fastest packet processing times when receiving financial market data. I see that when the NIC receives a packet, it puts it in memory ...
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0answers
287 views

Restoring in-memory/swapped page state on resume from hibernation

I'm a big fan of Linux's hibernation support, which works extremely well on all the (admittedly slightly older) hardware I've tried it on. I highly prefer it to full shutdown and power up. There's ...
18
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10answers
2k views

Filter file by line number

Given a file L with one non-negative integer per line and text file F, what would be a fast way to keep only those lines in F, whose line number appears in file L? Example: $ cat L.txt 1 3 $ cat F....
3
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1answer
857 views

Io redirection vs file logging performance c/c++

Is there a performance difference from a latency point of view if we do a regular printf and redirect stdout to a file when running the program ( e.g., ./a.out > log.txt 2>&1 ) vs using fprintf ...
2
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2answers
775 views

Code for submitting job on cluster

I use the following code to submit a job on a cluster, but I don't know what these code means. Can some one explain me what the following code means if possible line-by-line. #!/bin/bash #PBS -N ...
3
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1answer
198 views

Using SLURM without a feature

Suppose my super computer has the following NODELIST's with the included features: NODELIST FEATURES NodeA (none) NodeB specialfeature and I am trying to benchmark performance ...
1
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1answer
434 views

apache mod_security and performance

I have a list of bots to block, so I was thinking that fail2ban could be a solution until I realized that mod_security would be more efficient in this kind of tasks. The number of bots is huge, so ...
2
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1answer
644 views

Strategies for building distributed computing system with hybrid Mac and Linux systems

I want to build a distributed computing system to run Matlab, C and other programming languages for scientific computing. Now I've several old Mac machines with Lion Mac OS installed acted as web ...
2
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1answer
879 views

tmpfs performance

I use avconv to make screen recording of gameplays on linux (yeah, I'm sorry, I am one of them, but I get more excited about the scripts than playing it self), but recently my harddrive has gone and ...
4
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2answers
2k views

Is there a drawback when using a chroot in high performance computing?

My (small) company uses an out-of-date linux (centos) software stack to run a proprietary software on a small cluster. Understandingly, IT is reluctant to upgrade since everything works now. I'd like ...
2
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1answer
2k views

How do I make a multi-threaded app use all the cores on Ubuntu under VMWare?

I have a multi-threaded C++ app (using pThreads) that processes a massive flat file that works great on Windows - uses all four cores on my puny CPU. Client wants to run the same code on Red Hat on a ...
42
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4answers
6k views

Why is Linux commonly used as operating system for supercomputers?

As of november 2010, Linux is used on 459 out of the 500 supercomputers of the TOP500. What are the reasons behind this massive use of Linux in the supercomputer space?