Messages in this thread |  | | Date | Wed, 30 Oct 1996 02:09:51 +0200 (EET) | From | Linus Torvalds <> | Subject | Re: 2.1.6 vs. 2.0.23 |
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On 29 Oct 1996, Alexander Sanda wrote: > > NOTE: I'am running 2.0.23 with Robert L. Krawitz's fast-pentium-memcpy > patch, so the results for 2.0.23 may be a little bit better than > expected.
Interesting. The only place the fpu-copy seems to show up in is the file re-read tests:
> *Local* Communication bandwidths in megabytes/second > ---------------------------------------------------- > Host OS Pipe TCP File Mmap Bcopy Bcopy Mem Mem > reread reread (libc) (hand) read write > --------- ------------- ---- ---- ------ ------ ------ ------ ---- ----- > darkstar Linux 2.1.6 43 16.7 41.5 66.5 43 40 73 83 > darkstar. Linux 2.0.23 35 15.1 46.0 64.8 43 40 73 83
Here it definitely looks like the effects of the pentium memcpy() code: the file re-read speed of your 2.0.23 is better than on 2.1.6, and is actually better than the libc bcopy.
I'd have expected the same thing in the pipe throughput too, but it seems the overhead for context switching the FPU state might impact the pipe throughput negatively (wild hand-waving here ;)
Linus
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