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Groups > comp.lang.java.programmer > #22642
| From | Joshua Cranmer đ§ <Pidgeot18@verizon.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: code for native functions |
| Date | 2013-02-28 20:32 -0600 |
| Organization | A noiseless patient Spider |
| Message-ID | <kgp3tv$eu4$1@dont-email.me> (permalink) |
| References | <c91c62aa-e453-4639-8b1f-6e48c2a4aa89@googlegroups.com> <5pqsi8ll07l62voutrp79njhijrsj8c9sv@4ax.com> <%juXs.110035$O02.46330@newsfe18.iad> <b9bvi8d9c4ssl0gfqgnfn69rfiectjq3ch@4ax.com> |
On 2/28/2013 1:21 PM, Roedy Green wrote: > You'd think a common high frequency counter of standard frequency > would not be rocket science. Look at the microarchitecture of a modern microprocessor, and you'll realize that it is a very hard problem. You're asking for effectively a 3GHz clock that presumably doesn't roll over soon--so more than 32 bits. That means you need a very fast increment circuit, and, to minimize gate delay, that means high-voltage too. Since you want it to be immune to the state of the processor, you have to use a high-voltage, high frequency circuit whether a chip is in high power or low power mode. If you want it to be shared, it has to be outside every processor core's power domain. Which means accessing this counter is going to require going through bus arbitrage mechanisms, which means you have unpredictable latencies on the order of hundreds of cycles. Shared, high frequency, low-latency access, predictable frequency. You can't get all of them. Or even most of them. -- Beware of bugs in the above code; I have only proved it correct, not tried it. -- Donald E. Knuth
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code for native functions bob smith <bob@coolfone.comze.com> - 2013-02-26 09:04 -0800
Re: code for native functions Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-02-26 09:43 -0800
Re: code for native functions Arne VajhĂžj <arne@vajhoej.dk> - 2013-02-26 19:17 -0500
Re: code for native functions Roedy Green <see_website@mindprod.com.invalid> - 2013-02-27 12:38 -0800
Re: code for native functions Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-02-27 12:50 -0800
Re: code for native functions Roedy Green <see_website@mindprod.com.invalid> - 2013-02-28 11:21 -0800
Re: code for native functions Joshua Cranmer đ§ <Pidgeot18@verizon.invalid> - 2013-02-28 20:32 -0600
Re: code for native functions Roedy Green <see_website@mindprod.com.invalid> - 2013-03-03 08:26 -0800
Re: code for native functions Arne VajhĂžj <arne@vajhoej.dk> - 2013-02-27 18:02 -0500
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