Compression ratio of zram

zramratio.rb

#!/usr/bin/env ruby
BLOCK_PATH='/sys/block'
MIB = 1024*1024
Dir.entries(BLOCK_PATH).select{|e| e.start_with? 'zram'}.each {|dev|
  orig = File.read(File.join BLOCK_PATH, dev, 'orig_data_size').to_i
  compr = File.read(File.join BLOCK_PATH, dev, 'compr_data_size').to_i
  printf "%s: %6.2f%% (%.2f MiB -> %.2f MiB)\n", dev, 100*compr/orig, orig/MIB, compr/MIB
}

zramratio.scm

#!/usr/bin/csi -s

(use srfi-1 srfi-13 utils posix files format)

(define BLOCK-PREFIX "/sys/block")

(define (metrics-for-dev name)
  (let* ((dev-path   (make-absolute-pathname BLOCK-PREFIX name))
         (compr-path (make-absolute-pathname dev-path "compr_data_size"))
         (orig-path  (make-absolute-pathname dev-path "orig_data_size")))
    (cons (string->number (string-trim-right (read-all compr-path)))
          (string->number (string-trim-right (read-all orig-path))))))

(define (format-size n)
  (format "~,2F MiB" (/ n (* 1024 1024))))

(define (format-dev name metrics)
  (let* ((compr (car metrics)) (orig (cdr metrics))
         (ratio (/ compr orig)))
    (format "~A: ~6,2F% (~A -> ~A)"
            name (* 100 ratio) (format-size orig) (format-size compr))))

(define (display-zram)
  (let* ((devs  (directory BLOCK-PREFIX))
         (zdevs (filter (lambda (name) (string-prefix? "zram" name)) devs)))
    (for-each (lambda (dev) (print (format-dev dev (metrics-for-dev dev)))) zdevs)))

(display-zram)

zramratio.zsh

#!/usr/bin/env zsh
for f in /sys/block/zram*; do
	orig=$(< $f/orig_data_size)
	compr=$(< $f/compr_data_size)
  printf '%s: %6.2f%% (%.2f MiB -> %.2f MiB)\n' \
    ${f:t} \
    $((100 * ${compr}.0 / ${orig})) \
    $((${orig} / 1048576.0)) \
    $((${compr} / 1048576.0))
done

bash only has integer arithmetic in 2012!?