<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 28/03/2009, at 10:27 PM, Jean-Yves Avenard wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Hi<br><br>2009/3/28 Tortise <<a href="mailto:tortise@paradise.net.nz">tortise@paradise.net.nz</a>>:<br><blockquote type="cite">If it is hyperthreading that's effectively splitting my CPU in half, wouldn't I be better to turn it off and make all of it<br></blockquote><blockquote type="cite">available?<br></blockquote><blockquote type="cite">When I get a chance to reboot I'll see if I can turn it off in the mBoard BIOS, unless you suggest otherwise?<br></blockquote><blockquote type="cite">{Ref <a href="http://ubuntuforums.org/showthread.php?p=895077">http://ubuntuforums.org/showthread.php?p=895077</a> the ht=on is not found.}<br></blockquote><br>It's a matter of choice I guess. The reports are rather split on that issue.<br><br>Personally, I always turned off hyperthreading in the BIOS, as the<br>gains aren't that great when it does make a difference and it can be<br>detrimental in many cases.<br></div></blockquote></div><div><br></div><div>HT can have some negative affects especially with code that needs a true CPU. The benefit really does depend on the core as with well behaved code you generally get 1.5 - 1.6 times a single core in performance. Occasionally with bad code (usually in my experience Java) you might get 90-95% of a core when it thrashes the CPU.</div><div><br></div><div>In the case of the VLC testing it won't make a lot of a difference, and might occasionally help. The HT code in a modern linux distro (read under 3 years old) is pretty good.</div><div><br></div><div>Steve</div><div><br></div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Steven Ellis - Technical Director<br>OpenMedia Limited<br>email - <a href="mailto:steven@openmedia.co.nz">steven@openmedia.co.nz</a><br>website - <a href="http://www.openmedia.co.nz/">http://www.openmedia.co.nz</a><br></div></div></span> </div><br></body></html>