<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - GCC memory starvation caused by flatten attribute with LTO" href="https://bugs.freedesktop.org/show_bug.cgi?id=77580#c2">Comment # 2</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - GCC memory starvation caused by flatten attribute with LTO" href="https://bugs.freedesktop.org/show_bug.cgi?id=77580">bug 77580</a> from <a class="email" href="mailto:doctorwhoguy@gmail.com" title="Patrick McMunn <doctorwhoguy@gmail.com>"> Patrick McMunn</a> <pre>I have wanted for a long time to be able to use LTO on xf86-video-intel, so I was very pleased when I found this patch submission. I tried it on the latest development version of the Intel driver from git. It applied successfully, and I was able to successfully compile the Intel driver using LTO instead of experiencing the seeming infinite compile time otherwise resulting from LTO. However, despite compilation being successful, my tests which involved glxgears, monitoring CPU usage, and watching videos on Youtube showed significantly poorer video performance with the LTO-compiled driver than without LTO. Though glxgears showed no discernible difference, Youtube performance was incredibly slow such that the audio portion of the video continued at normal speed while the video lagged progressively further behind in slow motion. I have no way of knowing if LTO is directly responsible for the poor performance or if the patch somehow led to poor optimization by LTO, but this should be investigated further. I used GCC 4.9.3 for the test. My Linux distro currently doesn't offer the 5.x branch of GCC, so I was unable to test with GCC 5.3.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>