On 10/7/18 11:57 AM, Pablo Sebastián Greco wrote:
Too many questions together... ;-)
El 7/10/18 a las 08:58, Robert Moskowitz escribió:
I have very recently learned about zram-swap. Fedora-29-arm is using it. It supposedly makes a considerable difference even over HD swap.
Do you have a link for me to read about that? I'd like to see some numbers on performance, specially on the CPU, because small ARM devices are not exactly fast to compress.
I did a quick check of my F29-arm system's use of zram. It is running zram 0.2-1. A quick look at usage with an Xfce DE accessed via vnc that has Firefox running:
# swapon -s Filename Type Size Used Priority /dev/zram0 partition 487304 10752 -2
# zramctl NAME ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS MOUNTPOINT /dev/zram0 lz4 475.9M 11.2M 4.3M 4.9M 2 [SWAP]
I would suspect the performance of lz4 over SD I/O is superior, plus less wear and tear of memory over SD. Here are a couple files and the systemctl status:
# cat /etc/zram.conf # The factor is the percentage of total system RAM to allocate to the ZRAM block device(s). FACTOR=2
# cat /etc/systemd/system/swap.target.wants/zram-swap.service [Unit] Description=Enable compressed swap in memory using zram DefaultDependencies=no Before=swap.target
[Service] Type=oneshot RemainAfterExit=yes TimeoutStartSec=30sec ExecStart=/usr/sbin/zramstart ExecStop=/usr/sbin/zramstop
[Install] WantedBy=swap.target
# systemctl -l --no-pager status zram-swap \u25cf zram-swap.service - Enable compressed swap in memory using zram Loaded: loaded (/usr/lib/systemd/system/zram-swap.service; enabled; vendor preset: disabled) Active: active (exited) since Fri 2018-06-22 11:12:12 EDT; 3 months 16 days ago Process: 437 ExecStart=/usr/sbin/zramstart (code=exited, status=0/SUCCESS) Main PID: 437 (code=exited, status=0/SUCCESS)
Jun 22 11:12:12 localhost zramstart[437]: Setting up swapspace version 1, size = 475.9 MiB (498999296 bytes) Jun 22 11:12:12 localhost zramstart[437]: no label, UUID=ba3bf62f-7bb0-4295-ad8c-2d26b000c3f8 Jun 22 11:12:12 localhost zramstart[437]: Activated ZRAM swap device of 499 MB Jun 22 11:12:12 localhost systemd[1]: Started Enable compressed swap in memory using zram.