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<body class='hmmessage'><div dir='ltr'><div> There is no good easy answer here. </div><div><br></div><div><br></div><div> You really want everything on the computer to use all of the </div><div> available resources, to service whatever the human wants done </div><div> as fast as possible, while remaining responsive e.g. to </div><div> requests to cancel or requests to increase the work load. </div><div><br></div><div><br></div><div> This is largely the job of the kernel, but it is an impossible job. </div><div> </div><div><br></div><div> To some extent we are obligated to over subscribe, in order</div><div> to provide the kernel more information.</div><div> But, again, it is an impossible job.</div><div><br></div><div> Besides it probably being NP complete to complete the submitted work</div><div> as soon as possible, we also don't know the user's priorities.</div><div><br></div><div> I could propose "pb 1" to mean run single threaded, putting</div><div> the burden on you to give. But that is a little rude.</div><div><br></div><div> Note that historically you didn't have as much flexibility here -- single core systems.</div><div><br></div><div><br></div><div> Anyway, how about the default be half? </div><div> Or 1 if <= 3 cores available? </div><div> I seem to have 4 cores, so this will help me. </div><div><br></div><div><br></div><div> I understand this is still not great, e.g. if you have 10</div><div> high priority single processors jobs, and one low priority</div><div> Modula-3 build, Modula-3 will by default use more than you wish.</div><div><br></div><div> </div><div> And yes, I understand disk are another resource.</div><div> And network -- disk can be on network.</div><div> You want to operate at the "edge of resource exhaustion" in general.</div><div><br></div><div><br></div><div> - Jay</div><br><br><br><br><div>> Date: Tue, 5 Jul 2016 18:36:45 +0200<br>> From: lemming@henning-thielemann.de<br>> To: rodney.m.bates@acm.org<br>> Subject: Re: [M3devel] defaulting to parallel backend?<br>> CC: m3devel@elegosoft.com<br>> <br>> <br>> On Mon, 4 Jul 2016, Rodney M. Bates wrote:<br>> <br>> > I prefer to use one fewer than the number of processors, so I can<br>> > web browse, read email, review code, etc. while waiting for a<br>> > compile. The compiler can saturate them all, making any other<br>> > stuff very slow.<br>> <br>> Slowdown can happen even earlier if the compilation is bound by disk <br>> access time.<br>> _______________________________________________<br>> M3devel mailing list<br>> M3devel@elegosoft.com<br>> https://m3lists.elegosoft.com/mailman/listinfo/m3devel<br></div> </div></body>
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