<!-- BaNnErBlUrFlE-BoDy-start -->
<!-- Preheader Text : BEGIN -->
<div style="display:none !important;display:none;visibility:hidden;mso-hide:all;font-size:1px;color:#ffffff;line-height:1px;height:0px;max-height:0px;opacity:0;overflow:hidden;">
Are you talking about the ack of RC connection? Or is it MPI’s scope? From: Raffenetti, Ken <raffenet@ anl. gov> Date: Tuesday, October 8, 2024 at 11: 05 AM To: discuss@ mpich. org <discuss@ mpich. org> Cc: Niyaz Murshed <Niyaz. Murshed@ arm. com>,</div>
<!-- Preheader Text : END -->
<!-- Email Banner : BEGIN -->
<div style="display:none !important;display:none;visibility:hidden;mso-hide:all;font-size:1px;color:#ffffff;line-height:1px;height:0px;max-height:0px;opacity:0;overflow:hidden;">ZjQcmQRYFpfptBannerStart</div>
<!--[if ((ie)|(mso))]>
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="padding: 16px 0px 16px 0px; direction: ltr" ><tr><td>
<table border="0" cellspacing="0" cellpadding="0" style="padding: 0px 10px 5px 6px; width: 100%; border-radius:4px; border-top:4px solid #90a4ae;background-color:#D0D8DC;"><tr><td valign="top">
<table align="left" border="0" cellspacing="0" cellpadding="0" style="padding: 4px 8px 4px 8px">
<tr><td style="color:#000000; font-family: 'Arial', sans-serif; font-weight:bold; font-size:14px; direction: ltr">
This Message Is From an External Sender
</td></tr>
<tr><td style="color:#000000; font-weight:normal; font-family: 'Arial', sans-serif; font-size:12px; direction: ltr">
This message came from outside your organization.
</td></tr>
</table>
</td></tr></table>
</td></tr></table>
<![endif]-->
<![if !((ie)|(mso))]>
<div dir="ltr" id="pfptBannere5wy3s0" style="all: revert !important; display:block !important; text-align: left !important; margin:16px 0px 16px 0px !important; padding:8px 16px 8px 16px !important; border-radius: 4px !important; min-width: 200px !important; background-color: #D0D8DC !important; background-color: #D0D8DC; border-top: 4px solid #90a4ae !important; border-top: 4px solid #90a4ae;">
<div id="pfptBannere5wy3s0" style="all: unset !important; float:left !important; display:block !important; margin: 0px 0px 1px 0px !important; max-width: 600px !important;">
<div id="pfptBannere5wy3s0" style="all: unset !important; display:block !important; visibility: visible !important; background-color: #D0D8DC !important; color:#000000 !important; color:#000000; font-family: 'Arial', sans-serif !important; font-family: 'Arial', sans-serif; font-weight:bold !important; font-weight:bold; font-size:14px !important; line-height:18px !important; line-height:18px">
This Message Is From an External Sender
</div>
<div id="pfptBannere5wy3s0" style="all: unset !important; display:block !important; visibility: visible !important; background-color: #D0D8DC !important; color:#000000 !important; color:#000000; font-weight:normal; font-family: 'Arial', sans-serif !important; font-family: 'Arial', sans-serif; font-size:12px !important; line-height:18px !important; line-height:18px; margin-top:2px !important;">
This message came from outside your organization.
</div>
</div>
<div style="clear: both !important; display: block !important; visibility: hidden !important; line-height: 0 !important; font-size: 0.01px !important; height: 0px"> </div>
</div>
<![endif]>
<div style="display:none !important;display:none;visibility:hidden;mso-hide:all;font-size:1px;color:#ffffff;line-height:1px;height:0px;max-height:0px;opacity:0;overflow:hidden;">ZjQcmQRYFpfptBannerEnd</div>
<!-- Email Banner : END -->
<!-- BaNnErBlUrFlE-BoDy-end -->
<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><!-- BaNnErBlUrFlE-HeAdEr-start -->
<style>
#pfptBannere5wy3s0 { all: revert !important; display: block !important;
visibility: visible !important; opacity: 1 !important;
background-color: #D0D8DC !important;
max-width: none !important; max-height: none !important }
.pfptPrimaryButtone5wy3s0:hover, .pfptPrimaryButtone5wy3s0:focus {
background-color: #b4c1c7 !important; }
.pfptPrimaryButtone5wy3s0:active {
background-color: #90a4ae !important; }
</style>
<!-- BaNnErBlUrFlE-HeAdEr-end -->
<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:Aptos;
panose-1:2 11 0 4 2 2 2 2 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:12.0pt;
font-family:"Aptos",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Aptos",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;
mso-ligatures:none;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style>
</head>
<body lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt">Are you talking about the ack of RC connection? Or is it MPI’s scope?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<div id="mail-editor-reference-message-container">
<div>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="color:black">From:
</span></b><span style="color:black">Raffenetti, Ken <raffenet@anl.gov><br>
<b>Date: </b>Tuesday, October 8, 2024 at 11:05</span><span style="font-family:"Arial",sans-serif;color:black"> </span><span style="color:black">AM<br>
<b>To: </b>discuss@mpich.org <discuss@mpich.org><br>
<b>Cc: </b>Niyaz Murshed <Niyaz.Murshed@arm.com>, nd <nd@arm.com><br>
<b>Subject: </b>Re: [mpich-discuss] MPI_Send over ibverbs<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt">An internal acknowledgement message is sent from the receiver to the sender indicating that a particular synchronous send operation was matched.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Ken</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<div id="mail-editor-reference-message-container">
<div>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in">
<b><span style="color:black">From: </span></b><span style="color:black">Niyaz Murshed via discuss <discuss@mpich.org><br>
<b>Date: </b>Tuesday, October 8, 2024 at 10:49</span><span style="font-family:"Arial",sans-serif;color:black"> </span><span style="color:black">AM<br>
<b>To: </b>discuss@mpich.org <discuss@mpich.org><br>
<b>Cc: </b>Niyaz Murshed <Niyaz.Murshed@arm.com>, nd <nd@arm.com><br>
<b>Subject: </b>Re: [mpich-discuss] MPI_Send over ibverbs</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:1.0pt;color:white">Thank you for the reply Joachim. ‘MPI_Ssend has the requirement to return after the message was matched at the receiver’ – From the above statement, how do the sender know
that the receiver called a matching receive? I am asking from the point</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:1.0pt;color:white">ZjQcmQRYFpfptBannerStart</span><o:p></o:p></p>
</div>
<div style="border:none;border-top:solid #90A4AE 3.0pt;padding:0in 0in 0in 0in;display:block!important;text-align:left!important;margin:0px!important;padding:16px!important;border-radius:4px!important;min-width:200px!important;background-color:#D0D8DC!important;border-top:#90a4ae!important" id="pfptBannero03wl87">
<div id="pfptBannero03wl87">
<div id="pfptBannero03wl87">
<p class="MsoNormal" style="margin-left:.5in;line-height:13.5pt;background:#D0D8DC">
<b><span style="font-family:"Arial",sans-serif;color:black">This Message Is From an External Sender
</span></b><o:p></o:p></p>
</div>
<div id="pfptBannero03wl87">
<p class="MsoNormal" style="margin-left:.5in;line-height:13.5pt;background:#D0D8DC">
<span style="font-family:"Arial",sans-serif;color:black">This message came from outside your organization.
</span><o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in;background:#D0D8DC"><span style="color:black"> </span><o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:1.0pt;color:white">ZjQcmQRYFpfptBannerEnd</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt">Thank you for the reply Joachim.</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt">‘MPI_Ssend has the requirement to return after the message was matched at <br>
the receiver’ –</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt">From the above statement, how do the sender know that the receiver called a matching receive?</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt">I am asking from the point of view of MPI_Send over RDMA.</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt">In case of RDMA, internally it will call rdma_send which does not know when a matching rdma_recv was called on destination. How do the sender knows when rdma_recv was called?</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<div id="mail-editor-reference-message-container">
<div>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in">
<b><span style="color:black">From: </span></b><span style="color:black">Joachim Jenke via discuss <discuss@mpich.org><br>
<b>Date: </b>Tuesday, October 8, 2024 at 9:42</span><span style="font-family:"Arial",sans-serif;color:black"> </span><span style="color:black">AM<br>
<b>To: </b>discuss@mpich.org <discuss@mpich.org><br>
<b>Cc: </b>Joachim Jenke <jenke@itc.rwth-aachen.de><br>
<b>Subject: </b>Re: [mpich-discuss] MPI_Send over ibverbs</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt">Hi,<br>
<br>
none of the MPI send calls has a requirement to return after the message <br>
was received. MPI_Send can return as soon as the caller can write to <br>
buffer without impact to the data being transferred. This might be after <br>
the data is put to the network, or the MPI library copied the data to an <br>
internal buffer.<br>
<br>
MPI_Ssend has the requirement to return after the message was matched at <br>
the receiver, which implies that the matching Receive was called. But it <br>
still does not require that the message was received at this point.<br>
<br>
Best<br>
Joachim<br>
<br>
Am 08.10.24 um 04:55 schrieb Niyaz Murshed via discuss:<br>
> Hi,<br>
> <br>
> Is there a way to check the implementation of MPI_Send?<br>
> <br>
> As I understand there is an implicit barrier which allows MPI_Send to <br>
> return only after the buffer is received by the destination.<br>
> <br>
> How is this communication done? How does the destination notify the <br>
> sender that buffer is received?<br>
> <br>
> How is this implemented when using rocev2 ?<br>
> <br>
> Regards,<br>
> <br>
> Niyaz<br>
> <br>
> <br>
> _______________________________________________<br>
> discuss mailing list discuss@mpich.org<br>
> To manage subscription options or unsubscribe:<br>
> <a href="https://urldefense.us/v3/__https:/lists.mpich.org/mailman/listinfo/discuss__;!!G_uCfscf7eWS!aTxlD8Xx22PDuMXv--UZcA68fdpz5fzzNTbFlnm4W8ILFpny-KqRwNDxs2-iX7Ob14g7ReYsSsFBpE5IiC8$">
https://lists.mpich.org/mailman/listinfo/discuss</a><br>
<br>
<br>
-- <br>
Dr. rer. nat. Joachim Jenke<br>
<br>
IT Center<br>
Group: High Performance Computing<br>
Division: Computational Science and Engineering<br>
RWTH Aachen University<br>
Seffenter Weg 23<br>
D 52074 Aachen (Germany)<br>
Tel: +49 241 80- 24765<br>
Fax: +49 241 80-624765<br>
jenke@itc.rwth-aachen.de<br>
<a href="https://urldefense.us/v3/__http:/www.itc.rwth-aachen.de__;!!G_uCfscf7eWS!aTxlD8Xx22PDuMXv--UZcA68fdpz5fzzNTbFlnm4W8ILFpny-KqRwNDxs2-iX7Ob14g7ReYsSsFBFKt98Uc$">www.itc.rwth-aachen.de</a></span><o:p></o:p></p>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
</html>