ppcopcodes: avoid TLB flushes for noop SR changes #104
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We do a linear scan in find_range (which is called on all TLB misses) to find the entries. The largest and most frequently hit entry is the system memory (which starts at 0). By ensuring that it's the first entry in the list, we end up only doing one iteration through the loop.
They happen surprisingly often, and flushing the TLB is expensive because we need to walk over all entries. Takes booting 10.2 on a Beige G3 from binary start to "Welcome to Macintosh" from 58s to 38s on my machine.
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They happen surprisingly often, and flushing the TLB is expensive because we need to walk over all entries.
Takes booting 10.2 on a Beige G3 from binary start to "Welcome to Macintosh" from 58s to 38s on my machine.
Also includes a small performance optimization for scanning address ranges on TLB cache misses.