zfs-patches/0013-Rewrite-fHits-in-arc_summary.py-with-SI-units.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: "Scot W. Stevenson" <scot.stevenson@gmail.com>
   3 Date: Sat, 4 Nov 2017 21:33:28 +0100
   4 Subject: [PATCH] Rewrite fHits() in arc_summary.py with SI units
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Complete rewrite of fHits(). Move units from non-standard English
  10 abbreviations to SI units, thereby avoiding confusion because of
  11 "long scale" and "short scale" numbers. Remove unused parameter
  12 "Decimal". Add function string. Aim to confirm to PEP8.
  13
  14 Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
  15 Reviewed-by: George Melikov <mail@gmelikov.ru>
  16 Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
  17 Signed-off-by: Scot W. Stevenson <scot.stevenson@gmail.com>
  18 Closes #6815
  19 (cherry picked from commit 88e4e0d5dd1800add5191633d65797ce1c2eb4cf)
  20 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  21 ---
  22  cmd/arc_summary/arc_summary.py | 62 ++++++++++++++++++++++--------------------
  23  1 file changed, 33 insertions(+), 29 deletions(-)
  24
  25 diff --git a/cmd/arc_summary/arc_summary.py b/cmd/arc_summary/arc_summary.py
  26 index 6b818edc7..cbb7d20bc 100755
  27 --- a/cmd/arc_summary/arc_summary.py
  28 +++ b/cmd/arc_summary/arc_summary.py
  29 @@ -111,36 +111,40 @@ def fBytes(b=0):
  30      return result
  31
  32
  33 -def fHits(Hits=0, Decimal=2):
  34 -    khits = (10 ** 3)
  35 -    mhits = (10 ** 6)
  36 -    bhits = (10 ** 9)
  37 -    thits = (10 ** 12)
  38 -    qhits = (10 ** 15)
  39 -    Qhits = (10 ** 18)
  40 -    shits = (10 ** 21)
  41 -    Shits = (10 ** 24)
  42 -
  43 -    if Hits >= Shits:
  44 -        return str("%0." + str(Decimal) + "f") % (Hits / Shits) + "S"
  45 -    elif Hits >= shits:
  46 -        return str("%0." + str(Decimal) + "f") % (Hits / shits) + "s"
  47 -    elif Hits >= Qhits:
  48 -        return str("%0." + str(Decimal) + "f") % (Hits / Qhits) + "Q"
  49 -    elif Hits >= qhits:
  50 -        return str("%0." + str(Decimal) + "f") % (Hits / qhits) + "q"
  51 -    elif Hits >= thits:
  52 -        return str("%0." + str(Decimal) + "f") % (Hits / thits) + "t"
  53 -    elif Hits >= bhits:
  54 -        return str("%0." + str(Decimal) + "f") % (Hits / bhits) + "b"
  55 -    elif Hits >= mhits:
  56 -        return str("%0." + str(Decimal) + "f") % (Hits / mhits) + "m"
  57 -    elif Hits >= khits:
  58 -        return str("%0." + str(Decimal) + "f") % (Hits / khits) + "k"
  59 -    elif Hits == 0:
  60 -        return str("%d" % 0)
  61 +def fHits(hits=0):
  62 +    """Create a human-readable representation of the number of hits.
  63 +    The single-letter symbols used are SI to avoid the confusion caused
  64 +    by the different "short scale" and "long scale" representations in
  65 +    English, which use the same words for different values. See
  66 +    https://en.wikipedia.org/wiki/Names_of_large_numbers and
  67 +    https://physics.nist.gov/cuu/Units/prefixes.html
  68 +    """
  69 +
  70 +    numbers = [
  71 +            [10**24, 'Y'],  # yotta (septillion)
  72 +            [10**21, 'Z'],  # zetta (sextillion)
  73 +            [10**18, 'E'],  # exa   (quintrillion)
  74 +            [10**15, 'P'],  # peta  (quadrillion)
  75 +            [10**12, 'T'],  # tera  (trillion)
  76 +            [10**9, 'G'],   # giga  (billion)
  77 +            [10**6, 'M'],   # mega  (million)
  78 +            [10**3, 'k']]   # kilo  (thousand)
  79 +
  80 +    if hits >= 1000:
  81 +
  82 +        for limit, symbol in numbers:
  83 +
  84 +            if hits >= limit:
  85 +                value = hits/limit
  86 +                break
  87 +
  88 +        result = "%0.2f%s" % (value, symbol)
  89 +
  90      else:
  91 -        return str("%d" % Hits)
  92 +
  93 +        result = "%d" % hits
  94 +
  95 +    return result
  96
  97
  98  def fPerc(lVal=0, rVal=0, Decimal=2):
  99 --
 100 2.14.2
 101