<div dir="ltr"><div>Hi everyone,</div><div><br></div><div>I just tested libreoffice performance between GCC + gold + libstdc++, clang + lld + libstdc++ and clang + lld + libc++ and noticed that gcc builds are slower (at least in this case). I will write a blog article with all the process to reproduce but small version, it just converts openDocument standart files (ODF 1.0 to 1.3) to PDF. There is no significant difference between both clang builds (changing lib C++ from libstdc++ to libc++) but gcc is slower than clang. Of course all builds don't use system libraries in this case to compare between lib C++, and builds are optimised and use LTO.<br></div><div><br></div><div> <span></span> <table style="font-family:"Liberation Sans";font-size:x-small" cellspacing="0" border="0"> <colgroup width="85"></colgroup> <colgroup width="103"></colgroup> <colgroup width="97"></colgroup> <colgroup width="85" span="2"></colgroup> <tbody style="font-family:"Liberation Sans";font-size:x-small"><tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left"><br></td> <td style="font-family:"Liberation Sans";font-size:x-small" align="left">OpenSUSE 7.2</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="left">Clang + libc++</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="left">Clang + std</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="left">Gcc + std</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 1</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,923045275</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">45,456441587</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">45,878275287</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">49,487550577</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 2</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,360027388</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,83441037</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,303120572</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,898307652</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 3</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,258628137</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,552443057</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,332110013</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,596628518</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 4</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,062155622</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,587905602</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,616728628</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,430735675</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 5</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">53,567235331</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,548408389</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,561502427</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,727024813</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 6</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,354870307</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,877387065</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,107891362</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,444552655</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 7</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">49,663738973</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,92048805</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,583599634</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,293633635</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 8</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">49,780141995</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,843555496</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,055990454</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,561677627</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 9</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">49,763425026</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,398042427</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,011950682</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,65275752</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Run 10</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,197944032</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,153460819</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,303763557</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,974880802</td> </tr> <tr style="font-family:"Liberation Sans";font-size:x-small"> <td style="font-family:"Liberation Sans";font-size:x-small" height="17" align="left">Average</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">50,4931212086</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">43,9172542862</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">44,4754932616</td> <td style="font-family:"Liberation Sans";font-size:x-small" align="right">47,8067749474</td> </tr> </tbody></table> </div><div><br></div><div>For information I use openSUSE Tumbleweed latest release.</div><div><br></div><div>I also noticed that libengine12 is really bigger with GCC but I've not have that data on me now.<br></div><div><br></div><div>I hope this could be an idea of improvement ! Next crazy test I would like to do is between MSVC and clang on windows ! But it seems harder !<br></div><div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Arnaud Versini</div></div></div></div>