Questions tagged [io]
I/O is an acronym for input/output, which refers to the mechanism or process for the transfer of information between one system or component and another.
646 questions
3 votes
1 answer
79 views
What is the best way to detect busy CPU cores for blk-mq request steering in Linux kernel?
I am trying to implement request steering in Linux kernel’s blk-mq layer to distribute I/O requests across CPU cores based on load. My goal is to redirect requests from busy cores to less busy ones to ...
- 31
0 votes
1 answer
71 views
USB Drive Read/Write Errors, Rasbperry Pi 3A+, Reproducable Error
Use Case I am using a SanDisk Ultra USB 3.0 Drive (128GB Capacity) with a Raspberry Pi 3A+ The drive is mounted using /etc/fstab: UUID=c85... /home/user/Videos/YouTube ext4 defaults,noatime,nofail 0 2 ...
0 votes
2 answers
161 views
when opening a FIFO for reading+writing, and blocking - how to tell if other side opened for reading or writing?
If I open a fifo for reading+writing in blocking mode: fd = open("foo", "O_RDWR"); Then it blocks until someone on the other end opens it for either reading or writing. But how do ...
- 117
0 votes
0 answers
125 views
disabling I8042 driver completely
"i8042 is still probing even though I disabled CONFIG_SERIO_I8042. Does it have dependent configurations? Even after passing kernel command-line arguments: i8042.nopnp i8042.noaux , I still see ...
- 11
2 votes
0 answers
76 views
dm-crypt IOPS amplification
I have a ZFS pool comprising a mirror comprising two partitions encypted with dm-crypt. $ zpool list -v data2 NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP ...
- 1,428
0 votes
1 answer
105 views
Can DPDK Work With UEFI SecureBoot Enabled - Kernel Lockdown Mode?
Apologies in advance if I have incorrect assumptions in the post. I'm still getting the hang of DPDK. Basically, I am trying to utilize DPDK on a Generation 2 Hyper-V VM that has Secure Boot enabled. ...
- 1
2 votes
1 answer
100 views
Which is better when using a program that produces output to STDOUT the program's output option or output redirection
Is there any advantage/disadvantage to using a commands output option (usually -o) if you can just use output redirection (>). Originally this question was specifically pertaining to cURL but after ...
- 23
0 votes
1 answer
204 views
How exactly are results being passed among processes via the pipes?
So Unix follows a uniform approach to I/O that allows programs to connect via pipes. I also know that to do that it uses file descriptors. But I heard someone saying that pipes allow attaching the ...
- 181
1 vote
1 answer
470 views
Slow write operation on NFS volume
I have a problem on NFS volumes that appeared two days ago. The problem seems related to write operations, with the following taking a longer time (10s of seconds) to complete : sed -i rm Editing and ...
- 11
4 votes
0 answers
121 views
Debian Bookworm - How to prevent block device seeking and probing when connected?
I have a small bootable system which requires access to storage devices, but not at the data level (i.e. just firmware commands), with the exception of a USB floppy drive whose data is accessed raw (...
2 votes
1 answer
332 views
Automatic flush of stream when reading input
I read in Advanced Programming in Unix Environment this: Line buffering comes with two caveats. First, the size of the buffer that the standard I/O library uses to collect each line is fixed, so I/O ...
- 135
12 votes
4 answers
2k views
Limit file IO speed
I am looking for a command similar to ionice and trickle and pv -L and tc - but which puts limits on IO to files. ionice looks at block devices on the local machine. I want this to work for file I/O ...
- 37.6k
1 vote
1 answer
255 views
Understanding `pgpgin` in `/proc/vmstat` as I/O Counters: Relationship with I/O Bandwidth Measurements
Hi Kernel I/O Experts, I have a question regarding the pgpgin and pgpgout counters in /proc/vmstat, specifically focusing on pgpgin. I’ve been exploring performance monitoring tools like vmstat and ...
- 161
1 vote
1 answer
150 views
How to find the parent process of child processes causing heavy IO
I would like to find the parent process for a large amount of small child processes performing small IO operations. For example, consider the following python script: import os import time import ...
- 233
0 votes
0 answers
41 views
How can I get the _real_ progress of dd, ignoring fast/staging buffers? [duplicate]
I'm using the dd command to write to a USB stick. My command is pretty straightforward: dd if=myimage.iso of=/dev/sdd bs=1M status=progress and indeed, I seem to be getting the progress reported: ...
- 11.1k