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Hi!<div><br><div><div>On Oct 9, 2007, at 12:10 AM, dormando wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><span class="Apple-style-span" style="-webkit-text-stroke-width: -1; ">Are increments atomic across SMP/multicore? It'd be hard to corrupt it, but I don't know off the top of my head if it's safe to ignore locking when you're just reading/writing to one set of 4-8bytes. I'll have to </span></div></blockquote><br></div><div>Not even close to being atomic. Not only do you have issues with multicore, you have worse issues with SMP because of the costs around synchronizing the variables across the CPU transport (aka the bus between the CPU's).</div><div><br class="webkit-block-placeholder"></div><div>When incrementing/changing values you need to wrap the write in a mutex if you want to be sure of the change.</div><div><br class="webkit-block-placeholder"></div><div>Cheers,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>-Brian</div><div> </div><div> <span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; 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; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; 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; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">--</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________________</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Brian "Krow" Aker, brian at tangent.org</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Seattle, Washington</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="http://krow.net/"><span class="Apple-style-span" style="color: rgb(0, 0, 238); -khtml-text-decorations-in-effect: underline; "><span class="Apple-style-span" style="color: rgb(0, 0, 238); -khtml-text-decorations-in-effect: underline; ">http://krow.net</span></span></a>/ <-- Me</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="http://tangent.org/"><span class="Apple-style-span" style="color: rgb(0, 0, 238); -khtml-text-decorations-in-effect: underline; "><span class="Apple-style-span" style="color: rgb(0, 0, 238); -khtml-text-decorations-in-effect: underline; ">http://tangent.org</span></span></a>/ <-- Software</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="http://exploitseattle.com">http://exploitseattle.com</a>/ <-- Fun</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________________</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">You can't grep a dead tree.</div><br class="Apple-interchange-newline"></span></span> </div><br></div></body></html>