<div dir="ltr">Guys, <div>It would be more helpful if everybody states their own experience with respect to kernel development.<div><div>It sounds more like a fight now. </div><div>:)<br></div>The question was originally asked by "CRISTIAN ANDRES".<br></div><div>He is nowhere in the conversation now.</div><div>Let's see if he has some specific query with respect to the ram<span style="background-color:rgb(248,249,250);font-family:arial,sans-serif;white-space:pre-wrap"> memory subsystem.</span></div><div><span style="background-color:rgb(248,249,250);font-family:arial,sans-serif;white-space:pre-wrap"><br></span></div><div><font face="arial, sans-serif"><span style="white-space:pre-wrap;background-color:rgb(248,249,250)">Cheers</span></font></div><div><span style="background-color:rgb(248,249,250);font-family:arial,sans-serif;white-space:pre-wrap">Sahil Gupta</span></div><div><br></div><br><div>
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<span style="color:transparent;font-size:0">10/03/19, 01:18:52 PM</span>
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<span style="color:transparent;font-size:0">10/03/19, 01:19:38 PM</span>
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<span style="color:transparent;font-size:0">10/03/19, 01:20:58 PM</span>
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</div></div><img width="0" height="0" class="mailtrack-img" alt="" style="display:flex" src="https://mailtrack.io/trace/mail/02aa1089e4aaf3a50d2521a73be9f970b1605926.png?u=1052462"></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Oct 3, 2019 at 12:56 PM Valdis Klētnieks <<a href="mailto:valdis.kletnieks@vt.edu" target="_blank">valdis.kletnieks@vt.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Thu, 03 Oct 2019 06:55:50 -0400, Ruben Safir said:<br>
<br>
> I wouldn't call that C code basic. Regardless, showing an example of a<br>
> driver that doesn't need math, and it might if you understood the high<br>
> level math, and your not aware of it, but predictive branching would<br>
> need it. <br>
<br>
See the kernel code that maintains statistical data on likely()/unlikely()<br>
under CONFIG_PROFILE_ANNOTATED_BRANCHES. Seems like "this likely() actually<br>
only triggers 3% of the time" isn't exactly higher math.<br>
<br>
There may be some magic going on in the chip hardware - but that's in the<br>
*hardware* and inaccessible to the programmer. I'll also point out that<br>
speculative execution has *other* problems.....<br>
<br>
> You can not calculate simple interest efficiently without calculus. <br>
<br>
Simple interest is *easy*. Amount * percent. Done. It's compound interest<br>
that only sort of needs calculus (and there only to understand the limiting<br>
case) - and even there I doubt any banks actually use calculus, just apply the<br>
iterative approach.<br>
<br>
// yearly interest compounded monthly<br>
for (i=0;i<num_months;i++) { balance += (balance * percent) /12;}<br>
<br>
I'd like to see you do it more efficiently using calculus. Especially if you<br>
have to take into account rounding to the nearest penny 36 times for a 3<br>
year loan. That stuff is why COBOL is still around. :)<br>
<br>
> calculus. This repeadely ends up being an issue of "if I don't know it,<br>
> I don't need it", which is wrong. More math helps you every time. Math<br>
<br>
Somehow I doubt that the Taniyama-Shimura-Weil conjecture is ever<br>
going to have any relevance inside the kernel.<br>
<br>
> is advanced logic. I can't tell you how many times I see folks brute<br>
> force their way to solutions that they should be using integration.<br>
<br>
Can you show an example of where the kernel needs to be using integration?<br>
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