Reorder buffer size

Reorder buffer size of various CPUs

Henry Wong has written a great program for measuring the size of the reorder buffer of the CPU it runs on, and Travis Downs has improved it. I have used these programs to measure the reorder buffer size on our microarchitecture collection. Further down you can find a file for each microarchitecture I measured, but first my interpretation: 
1/4    0   11   19 <- Travisdowns test
ROB       XMM  YMM
size GPRs regs regs year microarchitecture   class
  ?    ?    ?    ?  2011 Bobcat              AMD low-end

 72   72   37    -  2003 K8                  AMD mainline
 72   72   72    -  2009 Phenom II
128   92  128   64  2015 Carrizo (Excavator)
192  145  144   66  2017 Zen
224  141  147  143  2019 Zen2
  ?    ?    ?    ?  2020 Zen3
                    
 32   32   32    -  2013 Silvermont          Intel low-end
 78   56   65    -  2016 Goldmont
 95   68   77    -  2017 Goldmont+
                    
 96   96   96    -  2007 Penryn              Intel mainline
128  128  128    -  2009 Lynnfield
168  131  112  112  2011 Sandy Bridge
168  116  110  110  2012 Ivy Bridge
192  142  134  134  2013 Haswell
224  151  150  150  2015 Skylake
352  247  203  203  2021 Rocket Lake
The Bobcat and Zen3 do not exhibit the step in the results that the others exhibit (maybe the Bobcat cannot overlap the execution of two main memory accesses enough to trigger the effect that the program is designed for; for the Zen3 I have no theory). Apparently one of the assumptions used in the measurement program does not hold for these CPUs.

Combining this with stuff from other sources, we get: 

ROB GPR FPR Year 
 64  33  44 2013 Jaguar                    AMD low-end
 72  72     2005 K8 Palermo (Sempron)      AMD mainline
 72  72  72 2009 Phenom II
128  92 128 2015 Carrizo (Excavator)
192 168 160 2017 Zen Zen1-3
224 180 160 2019 Zen2
256 192 160 2020 Zen3
320 224 192 2022 Zen4

ROB GPR FPR XMM YMM ZMM Year
 32  32  32  32         2013 Silvermont                Intel low-end
 78                     2016 Goldmont
 95                     2017 Goldmont+
208                     2020 Tremont
256                     2021 Gracemont
                       
126                     2002 Northwood (Pentium 4)      Intel mainline Netburst
                        
 40                     1999 Coppermine (Pentium III)   Intel mainline P6-based
 96                     2007 Yorkfield (Core 2 Quad)
 96                     2007 Penryn (45nm Core 2)
128                     2009 Lynnfield (Core ix-xxx)
168                     2011 Sandy Bridge (Core ix-2xxx)
168                     2012 Ivy Bridge (Core ix-3xxx)
192                     2013 Haswell (Core ix-4xxx)
224                     2015 Skylake (Core ix-6xxx)
352 280 224 224 224 224 2019 Sunny/Willow Cove
512 288 320 320 320 220 2021 Golden Cove

ROB GPR FPR Year
192         2013 Apple A7 Cyclone
560         2019 Apple A13 Lightning
630 354 384 2020 Apple A14/M1 Firestorm, more info, more on the microarchitecture 


ROB GPR FPR Year
128         2016 Cortex A72                 ARM big
128         2018 Cortex A76 & Neoverse N1
160         2019 Cortex A77
160         2020 Cortex A78
160 147 124 2021 Cortex-A710
            
224         2020 Cortex-X1 (A78 sibling) ARM bigger
288         2021 Cortex-X2 (A710 sibling)
320         2022 Cortex-X3
            
256         2021 Neoverse V1 (A78 sibling) ARM biggest


ROB GPR FPR Year 
 96  96  96 2015 Samsung M1              Samsung big (Aarch64 architecture)
100  96  96 2017 Samsung M2
228 192 192 2018 Samsung M3
228 192 176 2019 Samsung M4
228 192 176 2020 Samsung M5
256 224 224 -    Samsung M6 (not released)

128         2017 Quallcomm Centriq 2400 (Falkor)
 
180         2018 Cavium Thunder X2
220 256 256 2021 Marvell Thunder X3
Cortex A73 and Cortex A75 do not use a reorder buffer. 
ROB  GPR FPR Vec Year
1120 228 240 128 2024 SiFive P870 ROB size apparently is 280 merged instructions
Anton Ertl
[ICO]NameLast modifiedSizeDescription
[DIR]Parent Directory  -  
[ ]penryn08-Jul-2019 17:48 6.0K 
[ ]lynnfield08-Jul-2019 17:43 6.0K 
[ ]k808-Jul-2019 17:37 6.0K 
[ ]silvermont09-Jul-2019 14:02 6.0K 
[ ]carrizo08-Jul-2019 17:15 6.0K 
[ ]bobcat09-Jul-2019 14:47 6.0K 
[ ]skylake08-Jul-2019 17:50 6.0K 
[ ]haswell08-Jul-2019 17:08 6.0K 
[ ]goldmont+08-Jul-2019 17:25 6.0K 
[ ]goldmont08-Jul-2019 17:22 6.0K 
[ ]zen08-Jul-2019 17:22 6.0K 
[ ]sandy-bridge08-Jul-2019 17:39 6.0K 
[ ]phenom208-Jul-2019 17:13 6.0K 
[ ]ivy-bridge08-Jul-2019 18:14 5.9K 
[DIR]Travisdowns/17-Apr-2021 19:08 -  
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