WAR & WAW - Intel 16-stage pipeline?

[srimks]

Hello,

Wish to know - Can WAR & WAW happen in current Intel Multi-core architecture (MCA) processor having 16-stage pipeline?

~BR

[Thomas_W_Intel]

Quoting - srimks

Hello,

Wish to know - Can WAR & WAW happen in current Intel Multi-core architecture (MCA) processor having 16-stage pipeline?

~BR

On current Intel processors, a WAR (write-after-read) hazard cannot happen, because writes are not reordered with older reads. A WAW (write-after-write) issue can happen under certain circumstances, because writes can be reordered with other writes executed with the CLFLUSH instruction, streaming stores,or string operations.
For further details, please refer to theIntel 64 and IA-32 Architectures Software Developers Manual, Volume 3A, Section 7.2.2.

Kind regards
Thomas

[srimks]

Quoting - Thomas Willhalm (Intel)

On current Intel processors, a WAR (write-after-read) hazard cannot happen, because writes are not reordered with older reads. A WAW (write-after-write) issue can happen under certain circumstances, because writes can be reordered with other writes executed with the CLFLUSH instruction, streaming stores, or string operations.
For further details, please refer to the Intel 64 and IA-32 Architectures Software Developers Manual, Volume 3A, Section 7.2.2.

Kind regards
Thomas

Really appreciate for clarifying. The section does descibes complete behaviour of WAR & WAW as asked.

~BR
Mukkaysh Srivastav

[srimks]

Quoting - Thomas Willhalm (Intel)

On current Intel processors, a WAR (write-after-read) hazard cannot happen, because writes are not reordered with older reads. A WAW (write-after-write) issue can happen under certain circumstances, because writes can be reordered with other writes executed with the CLFLUSH instruction, streaming stores,or string operations.
For further details, please refer to theIntel 64 and IA-32 Architectures Software Developers Manual, Volume 3A, Section 7.2.2.

Kind regards
Thomas

Hello Thomas,

Could you share the links for other Intel latest (March'2009) documents like - Intel Arch. Opt. Manual, Vol1 & Vol2 Inst. Manual, SPG-3B, etc.

I do have older(2007-2008) ones.

~BR