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Re: [kmip] Groups - Sun 64-bit Binary Alignment Proposal v2 (Sun64-bit Binary Alignment Proposal.pdf) uploaded

From
Matt Ball <>
Date
2009-05-06T19:17:36+00:00
ID
Thread
Re: [kmip] Groups - Sun 64-bit Binary Alignment Proposal v2 (Sun64-bit Binary Alignment Proposal.pdf) uploaded
Hi Scott,

Scott Kipp wrote:
> Matt,
>
> When I look at your two most recent proposals posted on the 6th and the
> 1st, here is a summary of the different values in section 9.1.1:
>
> Proposal	Item Tag	Item Type
> 32 Bit	32 bits	32 bits
> 64 bit	3 byte	1 byte
>
> Please help me understand where the 16 bit fields are.
>
>   
The details are more subtle.  I probably need to create a picture to do
this justice.  Here's a brief description:

32-bit Proposal:

32-bit Tag:  '42' | (00 or 01) | (16-bit Tag enumeration)
32-bit Type:  00 00 00 (8-bit type)

64-bit Proposal:

24-bit Tag: ('42' or '54') | (16-bit Tag enumeration)
8-bit Type: (8-bit type)

The nuance is that in the 64-bit proposal, the leading 16-bits of the
Tag are consolidated to 8-bits, leaving 16-bits for general Tag values. 
I'll put a nice picture together to describe this.
> Do you have any data as to how long it will take to process 32 bit or 64
> bit fields with 64 bit processors?  Won't the difference be in the
> microsecond range?  I don't think they will amount to much difference
I don't know what the performance difference is.  I did hear of others
in the group, though, who were noticing the mis-alignment issue in
relation to 64-bit timestamps.  Can anyone comment?

Cheers,
-Matt
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