<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"><meta name="Generator" content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
text-align:right;
direction:rtl;
unicode-bidi:embed;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.WordSection1
{page:WordSection1;}
--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Hi,</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
I have noticed the following method always adds a jitted method (looking at the ".NET CLR Jit" performance counter) when it is run:</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
def f():</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> d = defaultdict(int)</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> d[0]</p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> </p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">I created my own implementation of defaultdict (in ipy):</p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">class defaultdict(dict):</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> def __init__(self, cls):</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
super(defaultdict, self).__init__()</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> self.cls = cls</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
def __getitem__(self, key):</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> if key not in self:</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
self[key] = self.cls()</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> return super(defaultdict, self).__getitem__(key)</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">And I noticed that it does not leak JIT and it works 200 times faster when running the method f().</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
Can you please look why this happens in the current implementation?</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Also I was wondering if there are any other utility methods that use similar code and probably will have the same problem.</p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> </p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Thanks, </p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">
Idan zalzberg</p><p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> </p></div></body></html>