<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

<meta name="Generator" content="Microsoft Word 15 (filtered medium)">

<style><!--

/* Font Definitions */

@font-face

        {font-family:"Cambria Math";

        panose-1:2 4 5 3 5 4 6 3 2 4;}

@font-face

        {font-family:Calibri;

        panose-1:2 15 5 2 2 2 4 3 2 4;}

@font-face

        {font-family:Aptos;

        panose-1:2 11 0 4 2 2 2 2 2 4;}

/* Style Definitions */

p.MsoNormal, li.MsoNormal, div.MsoNormal

        {margin:0cm;

        font-size:11.0pt;

        font-family:"Calibri",sans-serif;

        mso-ligatures:standardcontextual;

        mso-fareast-language:EN-US;}

a:link, span.MsoHyperlink

        {mso-style-priority:99;

        color:#0563C1;

        text-decoration:underline;}

p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph

        {mso-style-priority:34;

        margin-top:0cm;

        margin-right:0cm;

        margin-bottom:0cm;

        margin-left:36.0pt;

        font-size:11.0pt;

        font-family:"Calibri",sans-serif;

        mso-ligatures:standardcontextual;

        mso-fareast-language:EN-US;}

span.EmailStyle22

        {mso-style-type:personal-reply;

        font-family:"Calibri",sans-serif;

        color:windowtext;}

.MsoChpDefault

        {mso-style-type:export-only;

        font-size:10.0pt;

        mso-ligatures:none;}

@page WordSection1

        {size:612.0pt 792.0pt;

        margin:72.0pt 72.0pt 72.0pt 72.0pt;}

div.WordSection1

        {page:WordSection1;}

/* List Definitions */

@list l0

        {mso-list-id:53699115;

        mso-list-template-ids:-903342754;}

@list l0:level1

        {mso-level-tab-stop:36.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level2

        {mso-level-tab-stop:72.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level3

        {mso-level-tab-stop:108.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level4

        {mso-level-tab-stop:144.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level5

        {mso-level-tab-stop:180.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level6

        {mso-level-tab-stop:216.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level7

        {mso-level-tab-stop:252.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level8

        {mso-level-tab-stop:288.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l0:level9

        {mso-level-tab-stop:324.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1

        {mso-list-id:631523392;

        mso-list-template-ids:197447650;}

@list l1:level1

        {mso-level-tab-stop:36.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level2

        {mso-level-tab-stop:72.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level3

        {mso-level-tab-stop:108.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level4

        {mso-level-tab-stop:144.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level5

        {mso-level-tab-stop:180.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level6

        {mso-level-tab-stop:216.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level7

        {mso-level-tab-stop:252.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level8

        {mso-level-tab-stop:288.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l1:level9

        {mso-level-tab-stop:324.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2

        {mso-list-id:867186504;

        mso-list-template-ids:-107715406;}

@list l2:level1

        {mso-level-tab-stop:36.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level2

        {mso-level-tab-stop:72.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level3

        {mso-level-tab-stop:108.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level4

        {mso-level-tab-stop:144.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level5

        {mso-level-tab-stop:180.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level6

        {mso-level-tab-stop:216.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level7

        {mso-level-tab-stop:252.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level8

        {mso-level-tab-stop:288.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l2:level9

        {mso-level-tab-stop:324.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3

        {mso-list-id:1808088766;

        mso-list-template-ids:-1662208390;}

@list l3:level1

        {mso-level-tab-stop:36.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level2

        {mso-level-tab-stop:72.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level3

        {mso-level-tab-stop:108.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level4

        {mso-level-tab-stop:144.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level5

        {mso-level-tab-stop:180.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level6

        {mso-level-tab-stop:216.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level7

        {mso-level-tab-stop:252.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level8

        {mso-level-tab-stop:288.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l3:level9

        {mso-level-tab-stop:324.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4

        {mso-list-id:2093701639;

        mso-list-template-ids:834816074;}

@list l4:level1

        {mso-level-tab-stop:36.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level2

        {mso-level-tab-stop:72.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level3

        {mso-level-tab-stop:108.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level4

        {mso-level-tab-stop:144.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level5

        {mso-level-tab-stop:180.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level6

        {mso-level-tab-stop:216.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level7

        {mso-level-tab-stop:252.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level8

        {mso-level-tab-stop:288.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

@list l4:level9

        {mso-level-tab-stop:324.0pt;

        mso-level-number-position:left;

        text-indent:-18.0pt;}

ol

        {margin-bottom:0cm;}

ul

        {margin-bottom:0cm;}

--></style>

</head>

<body lang="EN-GB" link="#0563C1" vlink="purple" style="word-wrap:break-word">

<div class="WordSection1">

<p class="MsoNormal">Hi Dean,<o:p></o:p></p>

<p class="MsoNormal"><o:p> </o:p></p>

<p class="MsoNormal">I currently don’t know what hardware issues sparse code causes on Intel. I need to check which hardware counters get worse. It might be far vs near.<o:p></o:p></p>

<p class="MsoNormal"><o:p> </o:p></p>

<p class="MsoNormal">Graviton has a counter which measures issues with code placement and can be used to measure code sparsity. I think this counter is not connected to the issue of far calls vs near call. I can run experiments when we use far calls and near

 calls for dense code.<o:p></o:p></p>

<p class="MsoNormal"><o:p> </o:p></p>

<p class="MsoNormal">Thanks,<o:p></o:p></p>

<p class="MsoNormal">Evgeny<o:p></o:p></p>

<p class="MsoNormal"><o:p> </o:p></p>

<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">

<p class="MsoNormal" style="margin-left:36.0pt"><b><span style="color:black">From:

</span></b><span style="color:black">hotspot-dev <hotspot-dev-retn@openjdk.org> on behalf of "dean.long@oracle.com" <dean.long@oracle.com><br>

<b>Date: </b>Wednesday 5 March 2025 at 22:24<br>

<b>To: </b>"hotspot-dev@openjdk.org" <hotspot-dev@openjdk.org><br>

<b>Subject: </b>RE: [EXTERNAL] RFD: Grouping hot code in CodeCache</span><span style="font-size:12.0pt;color:black;mso-ligatures:none;mso-fareast-language:EN-GB"><o:p></o:p></span></p>

</div>

<div>

<p class="MsoNormal" style="margin-left:36.0pt"><span style="font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>

</div>

<div>

<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" width="622" style="width:466.5pt;margin-left:36.0pt;border-collapse:collapse">

<tbody>

<tr style="height:15.25pt">

<td width="622" valign="top" style="width:466.5pt;border:solid #ED7D31 1.5pt;padding:0cm 5.4pt 0cm 5.4pt;height:15.25pt">

<p><strong><span style="font-family:"Calibri",sans-serif;color:black;background:#FFFF99">CAUTION</span></strong><span style="color:black;background:#FFFF99">: This email originated from outside of the organization. Do not click links or open attachments unless

 you can confirm the sender and know the content is safe.</span><o:p></o:p></p>

</td>

</tr>

</tbody>

</table>

</div>

<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>

<div>

<p style="margin-left:36.0pt">Just to clarify, if grouping helps, does that mean the reason for the performance impact of sparse code is mainly due to far calls vs near calls?<o:p></o:p></p>

<p style="margin-left:36.0pt">dl<o:p></o:p></p>

<div>

<p class="MsoNormal" style="margin-left:36.0pt">On 3/5/25 10:41 AM, Astigeevich, Evgeny wrote:<o:p></o:p></p>

</div>

<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">Hi Vladimir,</span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"> </span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">This is JDK-8326205: Implement grouping hot nmethods in CodeCache.</span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"> </span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">As I managed to synthesize a benchmark (<a href="https://github.com/openjdk/jdk/pull/23831">https://github.com/openjdk/jdk/pull/23831</a>) to demonstrate performance impact of sparse code, I’d

 like to discuss a possible solution of the sparse code.</span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"> </span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">High level, a solution is:</span><o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l2 level1 lfo1">

<![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><span lang="EN-US">Detect hot code.</span><span lang="EN-US">

</span><o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l2 level1 lfo1">

<![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><span lang="EN-US">Group hot code.</span><span lang="EN-US">

</span><o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l2 level1 lfo1">

<![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><span lang="EN-US">Maintain grouped code.</span><span lang="EN-US">

</span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"> </span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">Downstream </span>

we tried two approaches:<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">

<![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><b>Static lists of methods (compile command):</b> Identify frequently used (hot) methods using test runs and provide static method lists to JVM in production. When JVM compiles a Java method and the method is on the list, JVM puts the

 code into to a designated code heap (HotCodeHeap). <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">

<![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      

<![endif]>Dynamic lists of methods (compiler directives): Profile an application in production and dynamically relocate identified hot methods to HotCodeHeap. Relocation was implemented with recompilation.

<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">The main advantage of static lists is zero profiling overhead in production. We do all profiling and analysis in test runs. Its problems are:<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l1 level1 lfo3">

<![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      

<![endif]>Training Run Accuracy: We need training runs to have execution paths closely mimicking production environments. Otherwise we put wrong methods into HotCodeHeap.

<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l1 level1 lfo3">

<![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><b>Method List Maintenance:</b> We need to rerun training to regenerate lists when application code changes. Training runs are expensive and time-consuming. They require long runs to guarantee we see all major execution paths. Updating

 lists in production can be as complex as application deployment <o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l1 level1 lfo3">

<![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">      

<![endif]>Method Placement Limitations: Methods marked for HotCodeHeap are permanently placed into HotCodeHeap. No mechanism to remove methods that become less frequently used.

<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">We addressed these problems with dynamic lists of methods. We implemented a Java agent that runs within the same JVM to dynamically detect and manage hot Java methods without prior method identification. The agent

 detects hot methods using JFR. The agent manages hot Java methods in HotCodeHeap with compiler directives. A new compiler directive marks methods with dynamic states ("hot" or "cold"). Methods marked by the “hot” state are recompiled and placed in HotCodeHeap.

 Methods marked by the “cold” state are eventually removed from HotCodeHeap.<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">Problems of this approach are:<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l4 level1 lfo4">

<![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]>It requires specific, complex modifications to compiler directive support: recompilation of Java methods affected by compiler directives changes. This functionality is unique to Java agent implementation and has limited potential for

 broader use. <o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l4 level1 lfo4">

<![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      

<![endif]>The agent cannot guarantee Java methods are moved to/removed from the HotCodeHeap because updates of compiler directives can fail.

<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l4 level1 lfo4">

<![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">      

<![endif]>The agent knows nothing about compiled code, e.g. whether it’s C1 or C2 compiled, code size, profile. This data can useful for deciding to move or not to move to HotCodeHeap.

<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l4 level1 lfo4">

<![if !supportLists]><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">      

<![endif]>Recompilations, especially C2, are expensive. Having many of them can cause performance issues. Also recompiled code might differ from the code we have detected as “hot”.

<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">Running these two approaches in production we learned:<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]>We detect 95% of actively used methods withing the first 30 minutes of an application run. This is with JFR profiling configured: 90 seconds session duration, sampling each 11 ms, 8 minutes between profiling sessions. We can find actively

 used methods faster if we reduce a pause between profiling sessions and sampling period. However it will increase the profiling overhead and affect application performance. With the current configuration, the profiling overhead is between 1% - 2%.

<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      

<![endif]>A set of actively used methods gets into the steady state (no new methods added to, no methods removed from) within the first 60 minutes.

<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">      

<![endif]>Static lists, when created from runs close to production, have 80% - 90% methods always in use. This does not change over time.

<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">      

<![endif]>Predicting the size of HotCodeHeap is difficult, especially with dynamic lists.

<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">We want to have grouping of hot method functionality as a part Hotspot JVM. We will group only C2 compiled methods. We can group JVMCI compiled methods, e.g. Graal, if needed. We need profiling precise enough

 to detect major Java methods. Low overhead is more important than precision.<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">We think we can have a solution which does not require a lot of code:<o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">5.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><span lang="EN-US">Detect hot code: we can an implementation based on the Sweeper:

<a href="https://github.com/openjdk/jdk17u/blob/master/src/hotspot/share/runtime/sweeper.hpp">

https://github.com/openjdk/jdk17u/blob/master/src/hotspot/share/runtime/sweeper.hpp</a>. We will use the handshakes mechanism, what the Sweeper used, to detect nmethods on the top of thread stacks.</span><span lang="EN-US">

</span><o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">6.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><span lang="EN-US">Group hot code: we have a draft PR <a href="https://github.com/openjdk/jdk/pull/23573">

https://github.com/openjdk/jdk/pull/23573</a>. It implements relocation of nmethods within CodeCache.</span><span lang="EN-US">

</span><o:p></o:p></p>

<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt;mso-list:l3 level1 lfo5">

<![if !supportLists]><span style="mso-list:Ignore">7.<span style="font:7.0pt "Times New Roman"">      

</span></span><![endif]><span lang="EN-US">Maintain grouped code: we will add an additional code heap where hot nmethods will be relocated to.</span><span lang="EN-US">

</span><o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">What do you think about this approach? Are there other possible solutions?<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">Thanks,<o:p></o:p></p>

<p class="MsoNormal" style="margin-left:36.0pt">Evgeny A.<o:p></o:p></p>

<p class="MsoNormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt">

<span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:none;mso-fareast-language:EN-GB"><br>

<br>

<br>

Amazon Development Centre (London) Ltd.Registered in England and Wales with registration number 04543232 with its registered office at 1 Principal Place, Worship Street, London EC2A 2FA, United Kingdom.<br>

<br>

<o:p></o:p></span></p>

</blockquote>

</div>

</div>

<br><br><br>Amazon Development Centre (London) Ltd.Registered in England and Wales with registration number 04543232 with its registered office at 1 Principal Place, Worship Street, London EC2A 2FA, United Kingdom.<br><br><br>

</body>

</html>