Hi, am Dienstag, 21. März 2023 um 23:26 schrieben Sie:
> Hello! The article is found at > https://pushbx.org/ecm/dokuwiki/doku.php?id=blog:pushbx:2023:0321_cpu_performance_comparison I mostly agree with you and your article, but: >> Conclusion >> >> CPU-bound benchmarks are much faster on a modern machine than they >> are on older ones. >> The frequency increase does not actually suffice to explain the >> speedup. >> Some things, like doing I/O, were not sped up nearly as much >> however. I tried posting a much longer response to this, but it was apparently rejected by the moderators. Here's a shorter one. > I/O has also vastly speedup (we have SSD speeds of up to 6 GB/sec). > Just not by doing IN/OUT, but by using memory mapped PCI devices. I think you're confusing two different things -- MMIO and DMA/Bus-Mastering. Whether I/O is PMIO or MMIO is pretty much irrelevant to the speed. For example, I/O port 201h (the analog joystick) and I/O port 92h (which controls A20 on some computers) are both VERY slow and would not be any faster if they were MMIO instead of PMIO. The speed depends on the I/O device, not the type of I/O mapping. Plus, I/O _can't_ be cached, whether PMIO or MMIO, so the cache(s) are irrelevant to I/O. SSD speeds are fast because they use bus-mastering, not because they use MMIO. The I/O ports are used to "control" the device, but the data from the SSD is transferred in and out of RAM using bus-mastering (which is fast because it doesn't use the CPU at all). _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
