Write to Read relaxations

This section presents a systematic study of memory type impact on write-to-read sequences, which the base TSO model relaxes. It is to be noticed that behaviour depends on the memory type of the variable that is read.

Read into uncached memory type

When the read of the sequence is from a page of type UC (Uncached), write-to-read order is not relaxed, whatever the memory type of the written variable is.

There are 18 such tests

TSO

Hardware

Model

CoreI5

CoreI5-dual

CoreI7

Chianti

Limoux

Teraram

Estephe

Barsac

Zdani

R+mfence+po+UC+UC

Allow

Ok, 0/3.7G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+UC+UC

Allow

Ok, 0/3.1G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+po+UC+WB

Allow

Ok, 0/3.7G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+UC+WB

Allow

Ok, 0/3.1G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+po+UC+WC

Allow

Ok, 0/3.7G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+UC+WC

Allow

Ok, 0/3.1G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+po+UC+WT

Allow

Ok, 0/2.8G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

—

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+UC+WT

Allow

Ok, 0/2.2G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

—

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

SB+mfence+po+UC+UC

Allow

Ok, 0/3.6G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+UC+UC

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+UC+UC

Allow

Ok, 0/3.7G

Forbid

Ok, 0/778M

Ok, 0/204M

Ok, 0/432M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+pontnas+UC+UC

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+po+UC+WB

Allow

Ok, 0/3.6G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+UC+WB

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+po+UC+WC

Allow

Ok, 0/3.6G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+UC+WC

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+po+UC+WT

Allow

Ok, 0/2.8G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

—

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+UC+WT

Allow

Ok, 0/2.2G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

—

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

Read into write combining memory type

When the read of the sequence is from a page of type WC (Write-Combine), write-to-read order is not relaxed, whatever the memory type of the written variable is.

There are 18 such tests

TSO

Hardware

Model

CoreI5

CoreI5-dual

CoreI7

Chianti

Limoux

Teraram

Estephe

Barsac

Zdani

R+mfence+po+WC+UC

Allow

Ok, 0/3.7G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+po+WC+WB

Allow

Ok, 0/3.7G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+po+WC+WC

Allow

Ok, 0/3.7G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+po+WC+WT

Allow

Ok, 0/2.8G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

—

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

SB+mfence+po+WC+UC

Allow

Ok, 0/3.6G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+po+WC+WB

Allow

Ok, 0/3.6G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+po+WC+WC

Allow

Ok, 0/3.6G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+WC+WC

Allow

Ok, 0/3.7G

Forbid

Ok, 0/778M

Ok, 0/204M

Ok, 0/428M

Ok, 0/863M

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+po+WC+WT

Allow

Ok, 0/2.8G

Forbid

Ok, 0/738M

Ok, 0/204M

Ok, 0/392M

—

Ok, 0/408M

Ok, 0/553M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

R+mfence+pontna+WC+UC

Allow

Ok, 0/3.1G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+WC+WB

Allow

Ok, 0/3.1G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+WC+WC

Allow

Ok, 0/3.1G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

R+mfence+pontna+WC+WT

Allow

Ok, 0/2.2G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

—

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/267M

SB+mfence+pontna+WC+UC

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+WC+WB

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+WC+WC

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+mfence+pontna+WC+WT

Allow

Ok, 0/2.2G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

—

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

SB+pontnas+WC+WC

Allow

Ok, 0/3.0G

Forbid

Ok, 0/624M

Ok, 0/180M

Ok, 0/240M

Ok, 0/863M

Ok, 0/456M

Ok, 0/192M

Ok, 0/66M

Ok, 0/173M

Ok, 0/227M

Read into write back memory type

When the read of the sequence is from a page of type WB (default, Write-Back), write-to-read order is relaxed, whatever the memory type of the written variable is.

There are 18 such tests

TSO

Hardware

Model

CoreI5

CoreI5-dual

CoreI7

Chianti

Limoux

Teraram

Estephe

Barsac

Zdani

R+mfence+po+WB+UC

Allow

Ok, 1.5M/3.7G

Allow

Ok, 119k/738M

Ok, 7.7k/204M

Ok, 7.4k/392M

Ok, 526k/863M

Ok, 204k/408M

Ok, 580k/553M

No, 0/66M

Ok, 54k/173M

Ok, 9/267M

Allow unseen

R+mfence+po+WB+WB

Allow

Ok, 1.3M/3.7G

Allow

Ok, 135k/738M

Ok, 5.3k/204M

Ok, 194k/392M

Ok, 147k/863M

Ok, 207k/408M

Ok, 389k/553M

Ok, 186/66M

Ok, 35k/173M

Ok, 182k/267M

R+mfence+po+WB+WC

Allow

Ok, 273M/3.7G

Allow

Ok, 42M/738M

Ok, 18M/204M

Ok, 38M/392M

Ok, 29M/863M

Ok, 42M/408M

Ok, 89M/553M

Ok, 5.1k/66M

Ok, 15M/173M

Ok, 426k/267M

R+mfence+po+WB+WT

Allow

Ok, 967k/2.8G

Allow

Ok, 118k/738M

Ok, 4.7k/204M

Ok, 7.9k/392M

—

Ok, 189k/408M

Ok, 598k/553M

Ok, 1/66M

Ok, 49k/173M

Ok, 4/267M

R+mfence+pontna+WB+UC

Allow

Ok, 528k/3.1G

Allow

Ok, 36k/624M

Ok, 6.4k/180M

Ok, 43k/240M

Ok, 175k/863M

Ok, 208k/456M

Ok, 14k/192M

No, 0/66M

Ok, 45k/173M

No, 0/267M

Allow unseen

R+mfence+pontna+WB+WB

Allow

Ok, 86M/3.1G

Allow

Ok, 8.1M/624M

Ok, 2.8M/180M

Ok, 6.2M/240M

Ok, 24M/863M

Ok, 11M/456M

Ok, 16M/192M

Ok, 983k/66M

Ok, 10M/173M

Ok, 6.9M/267M

R+mfence+pontna+WB+WC

Allow

Ok, 155M/3.1G

Allow

Ok, 14M/624M

Ok, 17M/180M

Ok, 21M/240M

Ok, 28M/863M

Ok, 38M/456M

Ok, 22M/192M

Ok, 4.3k/66M

Ok, 15M/173M

Ok, 423k/267M

R+mfence+pontna+WB+WT

Allow

Ok, 84M/2.2G

Allow

Ok, 14M/624M

Ok, 18M/180M

Ok, 19M/240M

—

Ok, 10M/456M

Ok, 11M/192M

Ok, 67k/66M

Ok, 8.4M/173M

Ok, 2.5M/267M

SB+WB+WB

Allow

Ok, 165M/3.8G

Allow

Ok, 9.4M/778M

Ok, 7.5M/236M

Ok, 4.7M/432M

Ok, 106M/927M

Ok, 14M/408M

Ok, 13M/553M

Ok, 347k/66M

Ok, 4.5M/173M

Ok, 5.2M/227M

SB+mfence+po+WB+UC

Allow

Ok, 1.4M/3.6G

Allow

Ok, 358k/738M

Ok, 977/204M

Ok, 13k/392M

Ok, 539k/863M

Ok, 231k/408M

Ok, 285k/553M

No, 0/66M

Ok, 21k/173M

Ok, 5/227M

Allow unseen

SB+mfence+po+WB+WB

Allow

Ok, 1.1M/3.6G

Allow

Ok, 52k/738M

Ok, 5.7k/204M

Ok, 64k/392M

Ok, 125k/863M

Ok, 103k/408M

Ok, 490k/553M

Ok, 535/66M

Ok, 19k/173M

Ok, 232k/227M

SB+mfence+po+WB+WC

Allow

Ok, 222M/3.6G

Allow

Ok, 47M/738M

Ok, 23M/204M

Ok, 43M/392M

Ok, 23M/863M

Ok, 10M/408M

Ok, 62M/553M

Ok, 62k/66M

Ok, 10M/173M

Ok, 2.1M/227M

SB+mfence+po+WB+WT

Allow

Ok, 1.9M/2.8G

Allow

Ok, 351k/738M

Ok, 95k/204M

Ok, 240k/392M

—

Ok, 264k/408M

Ok, 876k/553M

Ok, 514/66M

Ok, 61k/173M

Ok, 586/227M

SB+mfence+pontna+WB+UC

Allow

Ok, 573k/3.0G

Allow

Ok, 96k/624M

Ok, 1.3k/180M

Ok, 109k/240M

Ok, 142k/863M

Ok, 180k/456M

Ok, 24k/192M

No, 0/66M

Ok, 21k/173M

Ok, 7/227M

Allow unseen

SB+mfence+pontna+WB+WB

Allow

Ok, 109M/3.0G

Allow

Ok, 10M/624M

Ok, 2.7M/180M

Ok, 12M/240M

Ok, 35M/863M

Ok, 12M/456M

Ok, 19M/192M

Ok, 443k/66M

Ok, 12M/173M

Ok, 7.4M/227M

SB+mfence+pontna+WB+WC

Allow

Ok, 124M/3.0G

Allow

Ok, 16M/624M

Ok, 21M/180M

Ok, 24M/240M

Ok, 22M/863M

Ok, 11M/456M

Ok, 17M/192M

Ok, 77k/66M

Ok, 11M/173M

Ok, 2.0M/227M

SB+mfence+pontna+WB+WT

Allow

Ok, 75M/2.2G

Allow

Ok, 10M/624M

Ok, 2.8M/180M

Ok, 12M/240M

—

Ok, 12M/456M

Ok, 19M/192M

Ok, 507k/66M

Ok, 11M/173M

Ok, 6.9M/227M

SB+pontnas+WB+WB

Allow

Ok, 1.3G/3.0G

Allow

Ok, 165M/624M

Ok, 66M/180M

Ok, 101M/240M

Ok, 569M/863M

Ok, 178M/456M

Ok, 73M/192M

Ok, 1.5M/66M

Ok, 73M/173M

Ok, 98M/227M

Read into write through memory type

When the read of the sequence is from a page of type WT (Write-Through), write-to-read order is relaxed, whatever the memory type of the written variable is.

There are 18 such tests

	TSO	Hardware	Model	CoreI5	CoreI5-dual	CoreI7	Limoux	Teraram	Estephe	Barsac	Zdani
R+mfence+po+WT+UC	Allow	Ok, 49k/2.8G	Allow	Ok, 6.6k/738M	Ok, 5.5k/204M	Ok, 3.8k/392M	Ok, 4.1k/408M	Ok, 28k/553M	No, 0/66M	Ok, 1.4k/173M	No, 0/267M
									Allow unseen		Allow unseen
R+mfence+po+WT+WB	Allow	Ok, 143k/2.8G	Allow	Ok, 8.0k/738M	Ok, 722/204M	Ok, 11k/392M	Ok, 2.6k/408M	Ok, 110k/553M	Ok, 2/66M	Ok, 7.1k/173M	Ok, 3.0k/267M
R+mfence+po+WT+WC	Allow	Ok, 360M/2.8G	Allow	Ok, 57M/738M	Ok, 23M/204M	Ok, 54M/392M	Ok, 93M/408M	Ok, 106M/553M	Ok, 204/66M	Ok, 26M/173M	Ok, 30k/267M
R+mfence+po+WT+WT	Allow	Ok, 45k/2.8G	Allow	Ok, 5.9k/738M	Ok, 5.2k/204M	Ok, 3.6k/392M	Ok, 3.3k/408M	Ok, 26k/553M	No, 0/66M	Ok, 1.2k/173M	Ok, 1/267M
									Allow unseen
R+mfence+pontna+WT+UC	Allow	Ok, 15k/2.2G	Allow	Ok, 1.8k/624M	Ok, 4.5k/180M	Ok, 3.2k/240M	Ok, 3.7k/456M	Ok, 199/192M	No, 0/66M	Ok, 2.0k/173M	No, 0/267M
									Allow unseen		Allow unseen
R+mfence+pontna+WT+WB	Allow	Ok, 52M/2.2G	Allow	Ok, 8.9M/624M	Ok, 401k/180M	Ok, 13M/240M	Ok, 8.4M/456M	Ok, 14M/192M	Ok, 6.7k/66M	Ok, 7.3M/173M	Ok, 586k/267M
R+mfence+pontna+WT+WC	Allow	Ok, 203M/2.2G	Allow	Ok, 19M/624M	Ok, 21M/180M	Ok, 28M/240M	Ok, 81M/456M	Ok, 27M/192M	Ok, 174/66M	Ok, 26M/173M	Ok, 29k/267M
R+mfence+pontna+WT+WT	Allow	Ok, 83M/2.2G	Allow	Ok, 18M/624M	Ok, 19M/180M	Ok, 26M/240M	Ok, 5.9M/456M	Ok, 10M/192M	Ok, 4.1k/66M	Ok, 4.2M/173M	Ok, 284k/267M
SB+WT+WT	Allow	Ok, 103M/2.9G	Allow	Ok, 37M/778M	Ok, 5.1M/236M	Ok, 34M/428M	Ok, 9.4M/408M	Ok, 8.0M/553M	Ok, 204k/66M	Ok, 3.3M/173M	Ok, 5.7M/227M
SB+mfence+po+WT+UC	Allow	Ok, 32k/2.8G	Allow	Ok, 169/738M	Ok, 199/204M	Ok, 261/392M	Ok, 3.4k/408M	Ok, 27k/553M	No, 0/66M	Ok, 1.0k/173M	No, 0/227M
									Allow unseen		Allow unseen
SB+mfence+po+WT+WB	Allow	Ok, 135k/2.8G	Allow	Ok, 7.9k/738M	Ok, 655/204M	Ok, 10k/392M	Ok, 3.0k/408M	Ok, 103k/553M	Ok, 2/66M	Ok, 10k/173M	Ok, 1.0k/227M
SB+mfence+po+WT+WC	Allow	Ok, 202M/2.8G	Allow	Ok, 52M/738M	Ok, 23M/204M	Ok, 48M/392M	Ok, 10M/408M	Ok, 60M/553M	Ok, 1.3k/66M	Ok, 8.6M/173M	Ok, 252k/227M
SB+mfence+po+WT+WT	Allow	Ok, 88k/2.8G	Allow	Ok, 17k/738M	Ok, 2.8k/204M	Ok, 13k/392M	Ok, 4.2k/408M	Ok, 46k/553M	No, 0/66M	Ok, 4.5k/173M	Ok, 105/227M
									Allow unseen
SB+mfence+pontna+WT+UC	Allow	Ok, 5.0k/2.2G	Allow	Ok, 86/624M	Ok, 316/180M	Ok, 207/240M	Ok, 3.0k/456M	Ok, 160/192M	No, 0/66M	Ok, 1.3k/173M	No, 0/227M
									Allow unseen		Allow unseen
SB+mfence+pontna+WT+WB	Allow	Ok, 72M/2.2G	Allow	Ok, 14M/624M	Ok, 1.7M/180M	Ok, 21M/240M	Ok, 9.2M/456M	Ok, 17M/192M	Ok, 6.7k/66M	Ok, 8.3M/173M	Ok, 546k/227M
SB+mfence+pontna+WT+WC	Allow	Ok, 99M/2.2G	Allow	Ok, 18M/624M	Ok, 21M/180M	Ok, 26M/240M	Ok, 10M/456M	Ok, 16M/192M	Ok, 1.3k/66M	Ok, 8.4M/173M	Ok, 240k/227M
SB+mfence+pontna+WT+WT	Allow	Ok, 72M/2.2G	Allow	Ok, 15M/624M	Ok, 1.2M/180M	Ok, 21M/240M	Ok, 9.1M/456M	Ok, 17M/192M	Ok, 2.5k/66M	Ok, 8.1M/173M	Ok, 561k/227M
SB+pontnas+WT+WT	Allow	Ok, 764M/2.2G	Allow	Ok, 170M/624M	Ok, 67M/180M	Ok, 103M/240M	Ok, 180M/456M	Ok, 72M/192M	Ok, 995k/66M	Ok, 73M/173M	Ok, 97M/227M