<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">That’s a harder topic and I wanted to think more about it. Here are the two issues with which I am most concerned:<div><br></div><div>1) We are defining the interaction of MPI with stuff that happens outside of MPI, in the programming language. Yes, we always sort of did, but this is in an area where many skilled people have made mistakes, and the likelyhood of an error is much higher. The lack of precision in these discussions reinforces my concern.</div><div><br></div><div>2) We are not considering the potential overhead that requiring other than a small set of RMA synchronization routines to guarantee some shared memory synchronization. The sense that I get is that the Forum is unconcerned about this, which I think is a serious mistake, and one for which I have yet to see a compelling use case.</div><div><br></div><div>Bill</div><div><br><div><div>On Jan 28, 2015, at 7:46 PM, Jeff Hammond <<a href="mailto:jeff.science@gmail.com">jeff.science@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;">Fine, but it would be helpful if you would respond to my comments</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;">about allowing point-to-point _synchronization_ on shared memory using</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;">PSCW, since those were the more germane ones anyways.</span></blockquote></div><br></div></body></html>