Questions tagged [cache]
cache is a component that stores data so future requests for that data can be served faster; the data stored in a cache might be the results of an earlier computation, or the duplicates of data stored elsewhere.
480 questions
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fork() Causes DMA Buffer in Physical Memory to Retain Stale Data on Subsequent Writes
I'm working on a C++ application on Ubuntu 20.04 that uses PCIe DMA to transfer data from a user-space buffer to hardware. The buffer is mapped to a fixed 1K physical memory region via a custom ...
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How to prioritize SSD page cache eviction over HDD with slower speed?
I have a large slow HDD and a small fast SSD. This is about reads not RAID. My desktop grinds to a near-halt when switching back to Firefox or man pages after (re/un)-loading 12+ GiB of Linux kernel ...
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What is the difference and relation between the "--default-cache-ttl" and "--max-cache-ttl" options?
About GPG is mentioned the gpg-agent and I read the following answer:
gpg does not ask for password
Where is mentioned the --default-cache-ttl and --max-cache-ttl options. So I found this official ...
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Alternate way to get the CPU cache size
I have a project where I need to get the size of the cache on my Linux machine. I don't know the linux distro, and the /etc/os-release file does not exist.
I only know the kernel and architecture:
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Synology SSD cache size requirement
I've been running a new Synology RS3621RPxs for several weeks, and my 4TB SSD cache shows:
Cache composition: Reusable (341 GB) / Total (3.6 TB)
If I'm reading that correctly, my nas isn't even using ...
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Share one SSD Cache across multiple volumes & storage pools on Synology NAS
I have a new Synology NAS with 2 storage pools, and I have one volume per pool.
I have added a single SSD to the NAS to serve as a cache, and was able to add it to the first storage pool. This is a ...
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Does linux have a cache for standard output?
I know that recently accessed files are cached into the RAM, but is there a cache for frequent commands?
For example, if I run cat file.txt multiple time, file.txt will be cached after the first ...
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Is there a FUSE-based caching solution for selective prefetching from a remote filesystem?
I am working with a remote parallel file system (CephFS), mounted at /mnt/mycephfs/, which contains a large dataset of small files (200 GB+). My application trains on these files, but reading directly ...
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SSL certa sha changed, but Chrome still uses old one
I was forced to change ssl certificate for one from my domains. So, cert changed, sha256 changed. Old cert was not expired yet, but it's now replaced with new one.
But, it looks like Chrome does not ...
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Radix Tree vs Multi-level bitmap
The Linux kernel (at least before using XArrays as far as I'm aware, which to my knowledge are wrappers around Radix Trees anyway) uses radix trees in its address_space structs which every file has. ...
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Whatever would the cached include except for the file pages?
Environment: a standby/idle running physical system with RHEL 6.9
Symptom: We have done some dd tests in order to observe the change of the buffers/cached size in the free -m cmd. After we had ...
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Do executables in different containers share shared objects that are define in the same common image layer?
I am investigating the memory impact of containerising two processes that depend on the same shared object. My main question is whether the shared object will be loaded in memory twice or not.
This ...
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`yum clean all` differs regarding handling disabled repositories
I'm porting some old build scripts from CentOS 7 to Rocky 8. I've noticed that the following command cleans all repository caches on Rocky 8, as opposed to just the caches of the one enabled ...
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Simulate slow disks in KVM to see effect of LVM cache in test setup
I'm setting up a Linux system in KVM (QEMU) to test the effect of adding a writeback LVM cache on a fast disk in front of a logical volume that resides on a set of very slow disks (a RAID1 LV). This ...
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how to manage size of /home .cache and .local folders
running RHEL 8.10 x86-64 on a server with many users,
/home is on a separate partition, and all user accounts as defined in /etc/passwd have their account under /home but there is a separate /data ...
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