Questions tagged [performance]

The speed at which a program runs

Filter by
Sorted by
Tagged with
2 votes
1 answer
19 views

Solving the USB drive/mass storage stall issue

Sadly the issue reported and described here: Pernicious USB-stick stall problem. Reverting workaround fix? and Is "writeback throttling" a solution to the "USB-stick stall problem"?...
Artem S. Tashkinov's user avatar
0 votes
0 answers
13 views

How to enable PMU in WSL2?

I am using WSL2 in Windows11 as my Linux host. Now I want to run perf in this WSL2, but I failed to do that with following errors. # uname -a Linux testhost 5.15.133.1-microsoft-standard-WSL2 #1 SMP ...
wangt13's user avatar
  • 396
0 votes
0 answers
26 views

Is it possibel to enable X86 PMU in QEMU emulation mode (without KVM)?

I am trying to run perf in my Linux system, but WSL2 and virtual-box 6.1 do NOT detect the hardware PMU in system. So, I installed qemu-system-x86_64 in Linux VM, and tried to run QEMU in emulation ...
wangt13's user avatar
  • 396
0 votes
1 answer
45 views

Fedora slow boot time

I recently removed Windows from my machine because I would like to adopt Linux as my main OS, specifically Fedora. Following are my machine specs: The system works pretty well, but the problem is ...
Sergio's user avatar
  • 1
2 votes
0 answers
35 views

A simple memcpy loop with stride of 8-16-32 Bytes, no L1 cache misses, what stalls backend cycles?

I am trying to understand the CPU cache performance in a single producer single consumer queue algorithm, but cannot pinpoint the cause of performance degradation in some cases. The following ...
xealits's user avatar
  • 2,143
2 votes
1 answer
212 views

Differences between qemu-i386 and Linux IA32 emulation

On x86-64 Linux, there are two options for running 32-bit applications: one can be built into the kernel itself via the option CONFIG_IA32_EMULATION (normally on for most kernels), and the other is ...
mcendu's user avatar
  • 123
0 votes
0 answers
40 views

fork() is very slow

I have a Linux server running Ubuntu 18.04 on a VM. Executing any task like ls -l or w frequently takes several seconds to finish. strace -c ls -l says ls only takes a few milliseconds, but running ...
Call of Guitar's user avatar
4 votes
1 answer
186 views

How many files in a directory is too many for ext4?

I wrote a Golang program to measure how long it takes to create 100 new files and read 100 existing files in a directory with 2k files vs a directory with 200k files: // Create 200k files in one ...
1f604's user avatar
  • 149
0 votes
0 answers
27 views

Undertanding the performance of replication in distributed storage

I have a bit of a struggle understanding the performance when using replication in distributed storage solutions (Linstor/DRBD in my case). I have 3 storage nodes, 10 NVMe each. Each NVMe has a write ...
huynp's user avatar
  • 3
1 vote
1 answer
28 views

Why do /dev/ramX devices have all 0's in /proc/diskstats?

Is there away way to turn on IO accounting for /dev/ramX block devices in Linux? I already tried echo 1 > /sys/block/ram1/queue/iostat but it did not work. Notice that all devices have stats except ...
KJ7LNW's user avatar
  • 435
0 votes
2 answers
90 views

there is a performance gap between distros? [closed]

I am new to linux. Now i have tried a bunch of distros, like debian ubuntu fedora and arch. I was wondering which distro offers the best performance. For reference my machine is laptop(huawei matebook ...
Dario Gallo's user avatar
2 votes
1 answer
65 views

How can a different controller explain this I/O?

My new NAS has 5 disks. They are all same model. sde is connected to the controller on the motherboard. sda-sdd is on the raid controller. Run 'pv /dev/sd[cde]' in parallel: Device rkB/s wkB/...
Ole Tange's user avatar
  • 35.4k
1 vote
1 answer
216 views

Which is the trigger of OOM killer, free or availaible memory in Linux?

I am working on an embedded Linux system which is on SOC platform. I have 2 machines ran the same memory workload, and I got following memory output. Machine 1. total used ...
wangt13's user avatar
  • 396
0 votes
0 answers
91 views

what's the fastest way of writing data to ffmpeg for video streams?

I'm live streaming my x11 screen to a v4l2 webcam device (/dev/video0) with FFmpeg through stdin : ffmpeg -re -probesize 32 -analyzeduration 0 -i pipe:0 -s 1280x720 -vf scale=1280:720 -preset veryfast ...
Hackermon's user avatar
0 votes
0 answers
17 views

Does NUMA need to be explicitly enabled before calling kernel API functions?

I'm converting a C++ application (running on Ubuntu) from single-socket to multi-socket. I would like to change the memory allocation to be NUMA-aware. I know the application will need to call C API ...
intrigued_66's user avatar
0 votes
0 answers
33 views

Optmization and tuning Linux Server (Mediaserver)

I rebuilt a server, specifically a mediaserver, based on debian 12 stable (kernel 6.1). CPU: i7-6700K(no overclock) RAM: 16GB DDR4 (dual channel) NIC: 2 of 2.5Gbit (bonding balance-tlb) (MTU bond0: ...
vincenzogianfelice's user avatar
0 votes
0 answers
40 views

Surprise in measuring UBIFS on NAND performance in Linux

I am working on an embedded Linux system (Linux-5.10.24), and there is a raw NAND FLASH as storage device on which UBI/UBIFS is used as file system. Now I am trying to measure and compare the UBIFS ...
wangt13's user avatar
  • 396
1 vote
0 answers
18 views

Latency on pselect caused by other user space processes

I have the following pre-condition on Linux: I'm using a process to read serial data using pselect on a serial device /dev/ttySX. Data comes in at a stable frequency of 400 Hz. To optimize latency of ...
nyquist's user avatar
  • 11
0 votes
1 answer
73 views

How to measure mmap I/O latency?

I have an application which appears to be slowing/blocking at the same time there's a lot of disk I/O going on, so I suspect it's I/O operations within the application which are blocking. I can't ...
phemmer's user avatar
  • 71.7k
0 votes
1 answer
26 views

Gather CPU utilisation or different workloads

I am trying to figure out for different workloads (CPU intensive, high DB IOPs etc), which compute series of cloud VM would be ideal. In order to do that I need to be able to get the CPU utilisation. ...
user14013917's user avatar
0 votes
0 answers
25 views

Splitting disk writes between two filesystems based on file extension

Background I am running a proprietary video & audio management application. It reads & writes large multimedia files but also uses a home-grown "database" for metadata. The database ...
kiler129's user avatar
  • 119
0 votes
0 answers
105 views

Pop Os taking long time to boot and start certain programs

I apologize that this question has been asked before. I looked at the answers on those questions but am still struggling. I have recently switched to Linux after using Windows for decades. I've been ...
MasterOblivious's user avatar
0 votes
1 answer
46 views

Http outperformed Http2 ,why, please help me to figure out?

I'm currently conducting performance testing on my NGINX web server container and I'm encountering some unexpected results. My tests show that HTTP performance is outperforming HTTP/2, despite SSL and ...
Mhd HZ's user avatar
  • 1
0 votes
2 answers
81 views

Can some command or script subtract lines in one file from another faster than grep?

I have a shell script that runs regularly and the following part of it causes a slowdown. grep -v -f RemoveTheseGoodIPs.txt FromTheseShadyIPs.txt > RemainingBadIPs.txt It works. It just takes 156 ...
Darius Dauer's user avatar
0 votes
2 answers
3k views

Are Intel or AMD processors generally regarded as "better" for Linux [closed]

Are there any differences between Intel and AMD processors in how Linux runs? Specifically in terms of performance, optimizations, and driver support? To simplify things, I am just talking about the ...
Luke's user avatar
  • 109
2 votes
1 answer
50 views

time difference of rm single tar file between large and small size

If I have a file data.tar and one is 1 MB in size versus one that is 10 GB in size versus one that is 10.0 TB in size (yes 10 terabytes is correct) why is there a time difference in doing a rm on ...
ron's user avatar
  • 6,515
0 votes
0 answers
57 views

Mismatch on checking memory usage in Linux

I am working on an embedded Linux system (kernel-5.10-24) where there is 64MB RAM in system. Now I am checking the memory usage in the system, and I found the mismatch of the data. First, the memory ...
wangt13's user avatar
  • 396
9 votes
1 answer
2k views

Low performance of encrypted SSD

I have a 128GB Somnambulist SSD. I know this brand is one of the worst. I measured the speed using GNOME Disk Utility, and it showed a read/write speed of 420/340. After encrypting the SSD with Debian ...
Daniel's user avatar
  • 353
2 votes
0 answers
206 views

How to find out what is causing decreased performance when USB-C power delivery is plugged in on a laptop running linux

I searched around and could not find an answer to this issue. For context: I am running ArchLinux on my Tuxedo InfinityBook 14 gen7 with RTX 3050 TI, the regular power adapter that came with the ...
Joao Paulo Farias's user avatar
1 vote
1 answer
230 views

Random wipe free space: dd if=/dev/urandom vs LUKS format-erase, which is more secure, any pitfalls?

The ArchLinux Wiki on dm-crypt advices overwriting new storage devices or partitions with random data before using them for encrypted volumes. There are two ways I have used to achieve this, but I ...
Mounaiban's user avatar
2 votes
1 answer
238 views

whisper.cpp takes a long time to start. Can this be avoided?

I am using https://unix.stackexchange.com/users/560724/georgi-gerganov 's whisper.cpp to transcribe recorded interviews. Many of these are short, a minuter or two. The problem is that whisper.cpp ...
d-b's user avatar
  • 1,891
1 vote
1 answer
183 views

sed performance using pattern space and hold space

Given a 425M sized text file with the following content: --START-- Data=asdfasdf Device=B Lorem=Ipsum --END-- --START-- Data=asdfasdf Lorem=Ipsum Device=A --END-- --START-- Device=B Data=asdfasdf --...
Hölderlin's user avatar
  • 1,188
0 votes
1 answer
685 views

Find command very slow in directory with tons of files and subdirectories

For about a week I've been waiting for the following command to complete find -type d -empty -print -delete >> empty-folder-deletion-log.txt but it is still going and it seems like it has a lot ...
The Movie Man's user avatar
0 votes
0 answers
412 views

Wi-Fi: too many "Tx excessive retries" and "Invalid misc"

I have an old laptop running LXLE (an Ubuntu-based distro) with a Broadcom BCM4311 Wi-Fi card, and although Wi-Fi connection works, data transfer speed is at roughly half of what it should be when ...
nvx's user avatar
  • 25
1 vote
0 answers
19 views

enhance performance in XEN VMs when copying lots of files inside the host

When I copy large amounts of data back and forth on my Debian XEN server in the host-VM, the server response in the webserver-VM with nginx becomes very slow. This is how I cause the problem in the ...
rubo77's user avatar
  • 28.8k
0 votes
0 answers
132 views

Is there some method of analyzing why a program is very slow to start?

I've bought a used computer with an NVME drive which seems very quick, but when I start some programs on it they are very slow. Once they start, they run fine, but the time it takes them to appear on ...
vfclists's user avatar
  • 7,487
0 votes
0 answers
47 views

Samba becomes laggy after a few hours of use, requires frequent deamon restarts

I have a Linux file server with about 40 file shares and 50 clients. The clients are not usually all connected at the same time, the active number of clients at any given time would be about 50%-75% ...
autobottodoggo's user avatar
0 votes
1 answer
26 views

SNMP forwarder to reduce load of switch

I have a core switch and running SNMPv3 on this. I need to reduce load of my switch. So if I have a SNMP Forwarder and do snmp on my core switch and other server snmp on my SNMP Forwarder, Do you know ...
PersianGulf's user avatar
  • 10.8k
1 vote
2 answers
139 views

Is there a performance penalty for backgrounding a process?

If I do: sleep 1 versus sleep 1 & wait $! will there be any difference in terms of CPU usage for spawning a foreground process versus a background process? Or will the performance of both lines ...
Maestro's user avatar
  • 191
1 vote
0 answers
72 views

Is it possible to maintain performance of "preferred" applications when certain resources are limited?

I work as a web developer, and due to the tools I generally have running (not to mention web browsers) I generally have high RAM usage at all times. Most of the time, my system handles this just fine. ...
Daniel Littlewood's user avatar
1 vote
0 answers
112 views

2TB NVMe slow in Linux only after booting Windows

My SSD is a 2TB PCIe 3.0 x4 M.2 NVMe (Mega Fastro MS200, some Korean brand, on sale under $100 in Germany). According to Windows smi_nvme_flash_id.exe utility it is a SM2262EN controller with Intel ...
munikiel's user avatar
0 votes
0 answers
34 views

Single core slow on i9 vs i3

Upgraded CPU from Intel Core i3-8350K to i9-9900K. Intel Core i3-8350K @ 4.00 GHz 1 Processor, 4 Cores, 4 Threads. Base clock rate 4.00GHz GenuineIntel Family 6 Model 158 Stepping 11 Intel Core i9-...
Err488's user avatar
  • 25
1 vote
0 answers
38 views

Optimize recovery after memory pressure

I have a machine that compiles large codebases, with 32 threads and 16 GiB RAM. The RAM is on the small side, but usually sufficient. When it isn't, however, the machine swaps out a few GiB of memory, ...
Simon Richter's user avatar
-1 votes
1 answer
70 views

http latency wild variance on localhost

Running on MBP M1 with 10 cores. Running 1 thread client (wrk) and 1 thread server (java). A youtube is also running on the system. Load average 2 out of 10. Except GC, which could be the reasons of ...
NicuMarasoiu's user avatar
1 vote
0 answers
248 views

How is the hardware TX queue selected by default?

NICs may have multiple hardware RX and TX queues, and there are several methods which allow choosing which RX and TX queues are used for a given flow/packet, though most are focused on the RX side. ...
BeeOnRope's user avatar
  • 547
0 votes
1 answer
107 views

I'm wondering why using cp in this way takes over 4 seconds [duplicate]

time cp /usr/local/bin/* /media/username/flash-drive-label real 0m4.142s user 0m0.007s sys 0m0.007s Normally using cp with wildcard (even when there are hundreds of files) like that never ...
thinksinbinary's user avatar
1 vote
0 answers
585 views

Is there any reason to use NFS 3 over version 4.2?

Consider a work environment with 100gbps type Infiniband switches, running on enterprise class servers having 512 GB of RAM and larger, with the operating system being RHEL 8.7 or very close to it. ...
ron's user avatar
  • 6,515
3 votes
2 answers
491 views

Why does higher CPU-usage slow down a task?

I am using whisper.cpp to transcribe some sound files. It is a very CPU heavy process so I try to find some optimal settings and therefore I have done some tests with the thread setting (-t) but the ...
d-b's user avatar
  • 1,891
3 votes
2 answers
389 views

Is SSD performance hindered by access to folder on SSD via symlink on conventional spinning rust HD?

I prefer to keep my OS and applications on one partition and /home/ on another. I intend to replace the current / drive with an SSD, then symlink /home/myuser/.local/ to a directory on the SSD because ...
dotancohen's user avatar
  • 15.8k
1 vote
1 answer
99 views

DPROBES (DTRACE_PROBE) for measuring high latency stuff under 1µsec

Currently, I'm analyzing the performance of a high latency application but I'm not confident in my measurements at all. So far, I have used DPROBES for instrumentation and BCC/funclatency for ...
Bahamas's user avatar
  • 113

1
2 3 4 5
21