<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Ahhh I see, I wasn’t looking in the right place.</div><div class=""><br class=""></div><div class="">I’ve spent the last few hours experimenting with the setjmp/longjmp intrinsics, and I don’t think they can achieve the desired result, for two reasons:</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>1. While switching stacks, it’s necessary to pass the original stack pointer (or setjmp pointer) to the longjmp destination, hence why the research paper suggests using a new calling convention. It doesn’t look like the longjmp intrinsic allows for passing parameters.</div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>2. Using setjmp/longjmp requires an extra branch (depending on whether setjmp returned zero or non-zero), which should not be necessary.</div><br class=""><div><blockquote type="cite" class=""><div class="">On Mar 27, 2020, at 5:01 PM, Eli Friedman <<a href="mailto:efriedma@quicinc.com" class="">efriedma@quicinc.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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;"><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><a href="https://llvm.org/docs/ExceptionHandling.html" style="color: blue; text-decoration: underline;" class="">https://llvm.org/docs/ExceptionHandling.html</a><span class="Apple-converted-space"> </span>.<o:p class=""></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">-Eli<span class="Apple-converted-space"> </span><o:p class=""></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="border-style: none none none solid; border-left-color: blue; border-left-width: 1.5pt; padding: 0in 0in 0in 4pt;" class=""><div class=""><div style="border-style: solid none none; border-top-color: rgb(225, 225, 225); border-top-width: 1pt; padding: 3pt 0in 0in;" class=""><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><b class="">From:</b><span class="Apple-converted-space"> </span>llvm-dev <<a href="mailto:llvm-dev-bounces@lists.llvm.org" class="">llvm-dev-bounces@lists.llvm.org</a>><span class="Apple-converted-space"> </span><b class="">On Behalf Of<span class="Apple-converted-space"> </span></b>Joshua Thomas Wise via llvm-dev<br class=""><b class="">Sent:</b><span class="Apple-converted-space"> </span>Friday, March 27, 2020 1:48 PM<br class=""><b class="">To:</b><span class="Apple-converted-space"> </span>Joerg Sonnenberger <<a href="mailto:joerg@bec.de" class="">joerg@bec.de</a>><br class=""><b class="">Cc:</b><span class="Apple-converted-space"> </span><a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a><br class=""><b class="">Subject:</b><span class="Apple-converted-space"> </span>[EXT] Re: [llvm-dev] Efficient Green Thread Context-Switching<o:p class=""></o:p></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">The first time you said “setjmp/longjmp intrinsics” I thought it was a typo, and that you were talking about the C standard library functions. If you’re actually talking about LLVM intrinsics, are they documented? I don’t see any intrinsics with those names in the language reference (<a href="https://llvm.org/docs/LangRef.html" style="color: blue; text-decoration: underline;" class="">https://llvm.org/docs/LangRef.html</a>).<o:p class=""></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div class=""><blockquote style="margin-top: 5pt; margin-bottom: 5pt;" class=""><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">On Mar 27, 2020, at 3:30 PM, Joerg Sonnenberger via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" style="color: blue; text-decoration: underline;" class="">llvm-dev@lists.llvm.org</a>> wrote:<o:p class=""></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div class=""><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">On Fri, Mar 27, 2020 at 02:58:03PM -0500, Joshua Thomas Wise wrote:<br class=""><br class=""><o:p class=""></o:p></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;" class=""><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Sorry, I certainly didn't mean to be dishonest. I was just repeating<br class="">one of the comparisons given by the research paper. Regardless, even<br class="">setjmp() uses a structure of 148 bytes in size (on my machine).<o:p class=""></o:p></div></blockquote><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><br class="">Let me repeat. Please take a look at the setjmp/longjmp intrinsics. On<br class="">support architectures they boil down to at most 5 pointers.<br class=""><br class="">Joerg<br class="">_______________________________________________<br class="">LLVM Developers mailing list<br class=""><a href="mailto:llvm-dev@lists.llvm.org" style="color: blue; text-decoration: underline;" class="">llvm-dev@lists.llvm.org</a><br class=""><a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" style="color: blue; text-decoration: underline;" class="">https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a></div></div></div></blockquote></div></div></div></div></blockquote></div><br class=""></body></html>