Mark Cuss wrote:
> I am working on optimizing some software and would like to be able to
> measure how long an instruction takes (down to the clock cycle of the CPU).
> I recall reading somewhere about a kernel time measurement called a "Jiffy"
> and figured that it would probably apply to this.
>
> If anyone has any tips on how to figure out how to do this I'd really
> appreciate it.
Jiffies are quite coarse-grained. On x86 you want the rdtsc instruction, while
on ppc you want mfrtcu/mfrtcl or mftbu/mftb depending on the version of the
chip. These are used as inline assembly, and if you do a google search you
should be able to find code snippets.
Chris
-- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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