This script displays some system memory statistics specifically aimed at zram swap partitions.
WARNING:
There has been a report that zram has changed its exposed interface
under /sys/devices/virtual/block/, so that this script is now broken.
This has been reported with Linus Kernel version 4.19.x.Unlike all other similar scripts I have seen, administration overhead is taken into consideration when calculating the compression rate, which gives you a more honest value.
Example output:
Physical memory: 490 MiB
Allocated by zram: 68 MiB ( 14.0%)
Normal usage: 372 MiB ( 76.0%)
Application I/O buffers: 0 MiB ( 0.1%)
System file cache: 41 MiB ( 8.5%)
Free: 6 MiB ( 1.2%)
zram advertised device size: 245 MiB ( 50.0% of physical RAM)
zram used size: 226 MiB ( 92.4% of advertised)
zram reserved but unused: 18 MiB ( 7.5% of advertised)
zram free: 0 MiB ( 0.0% of advertised)
Additional non-zram swap used: 222 MiB ( 90.6% in addition)
zram compression statistics:
Zeroed pages: 7 MiB ( 3.3% of used swap)
Original data size: 218 MiB
Compressed data size: 61 MiB ( 27.9% of orig, rate 3.57)
Admin overhead: 7 MiB ( 12.8% of compressed size)
In other words, lost: 68 MiB of RAM,
and gained: 226 MiB of fast swap.
Overall compr swap size: 30.4% of orig used size, rate 3.28