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GoldenEye 007 Nintendo 64 Community, GoldenEye X, Nintendo 64 Games Discussion GoldenEye Cheats, GoldenEye X Codes, Tips, Help, Nintendo 64 Gaming Community
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zoinkity 007
Joined: 24 Nov 2005 Posts: 1697
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Posted: Fri Mar 31, 2023 9:35 am Post subject: N64 Data Access Rates |
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If you've ever been interested in how quickly an N64 / 64DD / iQue can read data different ways, then you might be interested in this:
http://www.bwass.org/bucket/access_rates.7z
These are a series of screenshots of a clocker, testing different hardware access rates on a console. The original purpose was to come up with a workaround for softpatching translations onto retail disks since DMAs are too fast, causing run conditions. That's why the transfer blocks sizes are a bit odd. The idea is to get real numbers for a real threaded enviroment, even if they're somewhat idealized.
The hardware:
- 64DD disk
- N64 maskrom (in this case the IPL which is set a smidge faster than DIPs but whatevs, was close enough to modem results)
- N64 flashcart
- iQue in mode 2
- an invalid address (bad request timeout)
The conditions tested:
- DMA, in multiple 0x140000 segments
- IO read using the libultra function; it locks and unlocks the IO queue each word read, checks PI ready, then reads a word
- "fast" IO, which only twiddles the locks once and loops the ready/read portion
- Disk read, seek, encode/decode rates
If you don't want to browse the pictures, the results:
Code: | 64DD time to read, irregardless of zone: 3779972 uSec
.: DMA avg. bytes/sec :.
maskrom 10653508
64Drive 5271286
iQue 6537210
invalid 12559214
.: IO avg. bytes/sec :.
maskrom 587088
64Drive 557954
iQue 36515
invalid 732837
.: Fast IO avg. bytes/sec :.
maskrom 1641785
64Drive 1417382
iQue 37928
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That's not a mistake. It really does take over a minute and a half to read the first zone one word at a time on an iQue. I thought the program locked ;*) It has to decrypt a whole 0x4000 block at a time; DMAs buffer the decrypted data but individual word reads require redecryption each request.
As you'd expect, it isn't really possible (or sensible) to clock emulators. They'll complete a DMA in only a few dozen uSec so transfer rates are effectively instantaneous. _________________ (\_/) Beware
(O.o) ze
(> <) Hoppentruppen! |
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MRKane 007
Joined: 11 Dec 2008 Posts: 1076
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Posted: Fri Mar 31, 2023 5:10 pm Post subject: |
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Very cool! Frankly I'm crazy impressed with the progress on the iQue - see I've got this dream where we might one day play GE and PD with silky framerates on actual hardware _________________ No Mr. Bond, I expect you to be re-coded! |
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zoinkity 007
Joined: 24 Nov 2005 Posts: 1697
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Posted: Fri Mar 31, 2023 9:05 pm Post subject: |
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That day is closer than you think ;*)
http://www.shootersforever.com/forums_message_boards/viewtopic.php?t=8236
Hoping the day of aftermarket multiplayer boxes arrives soon. Those are hilariously expensive.
PD will be...awful to say the least, no idea where to stick the save files (eeprom + controller paks all buffered in rdram? Aegh...) but wow, if it's even half what GE pulls down would be worth it. _________________ (\_/) Beware
(O.o) ze
(> <) Hoppentruppen! |
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