By: David Kanter (dkanter.delete@this.realworldtech.com), August 31, 2007 5:41 am
Room: Moderated Discussions
Michael S (already5chosen@yahoo.com) on 8/31/07 wrote:
---------------------------
>Mr. Camel (a@b.c) on 8/31/07 wrote:
>---------------------------
>>I am trying to compare Beckton's and Tukwila's CSI bandwidths per socket (per socket
>>bandwidth = PSB for the rest of this post). I know that the following calculations
>>will be wrong, but I am hoping that some knowledgeable person will post a reply and correct me.
>>
>>David's article stated that Beckton's per socket bandwidth will be up to 10X that
>>of it's predecessor. I am assuming that the predecessor is Tigerton (or the 45
>>nm version of Tigerton). So from currently available information, Tigerton's PSB
>>will be 34/4 = 8.5 GB/s. This means that Beckton's PSB will be 85 GB/s. The article
>>gives a number for Tukwila's bandwidth but I am not sure if it is the per core bandwith
>>or the PSB. If we assume David is referring to the PSB (160 GB/s), the Tukwila's
>>platform will have roughly 2X the bandwidth of Beckton's >>platform.
I don't think you should read everything I wrote quite so literally.
>Full CSI link a 6.4MT/s delivers 12.8 GB/s in the read >direction or 11.4 GB/s in
>the write direction.
Where did you get those numbers from? Are you subtracting the bits used for CRC?
6.4GT/s * 20 bit lanes > 12.8GB/s
I also agree that the bandwidths are not quite comparable for x86 and IPF.
DK
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>Mr. Camel (a@b.c) on 8/31/07 wrote:
>---------------------------
>>I am trying to compare Beckton's and Tukwila's CSI bandwidths per socket (per socket
>>bandwidth = PSB for the rest of this post). I know that the following calculations
>>will be wrong, but I am hoping that some knowledgeable person will post a reply and correct me.
>>
>>David's article stated that Beckton's per socket bandwidth will be up to 10X that
>>of it's predecessor. I am assuming that the predecessor is Tigerton (or the 45
>>nm version of Tigerton). So from currently available information, Tigerton's PSB
>>will be 34/4 = 8.5 GB/s. This means that Beckton's PSB will be 85 GB/s. The article
>>gives a number for Tukwila's bandwidth but I am not sure if it is the per core bandwith
>>or the PSB. If we assume David is referring to the PSB (160 GB/s), the Tukwila's
>>platform will have roughly 2X the bandwidth of Beckton's >>platform.
I don't think you should read everything I wrote quite so literally.
>Full CSI link a 6.4MT/s delivers 12.8 GB/s in the read >direction or 11.4 GB/s in
>the write direction.
Where did you get those numbers from? Are you subtracting the bits used for CRC?
6.4GT/s * 20 bit lanes > 12.8GB/s
I also agree that the bandwidths are not quite comparable for x86 and IPF.
DK