librelane playground

No. 114 / project of 147 on the ladder

PTW aux owner

introduces — PTW aux-owner counters; A/D-write block accounting; PTW negative result

harden statelast run2026-05-06
signoff
  • DRCNOT RUN
  • LVSNOT RUN
  • antennaNOT RUN
artifacts

P114 measures whether the page-table walker has safe auxiliary-read opportunities. In this shell workload it does not.

checkresult
Verilator buildPASS
BusyBox shell workload reaches P114-FILE-OKPASS
PTW aux candidate countersPASS
Hardened layoutNOT RUN
countervalue
fetch PTW aux candidates0
LSU PTW aux candidates0
A/D write blocks73
metricP113P114
shell window cycles64,307,79764,501,127
S_MEM cycles27,674,92627,708,075
shell phases label P114 shell workload cycles 218,442,605 cpi 2.53
  1. kernel banner to /init 116,714,676 53.6%
  2. /init to shell banner 1,058,122 0.5%
  3. shell banner to first command 35,540,613 16.3%
  4. echo command 1,649 0%
  5. uname -a 2,365,183 1.1%
  6. ls /bin /usr/share 31,830,494 14.6%
  7. cat sample file 2,666,379 1.2%
  8. touch/write/cat/rm /tmp file 11,672,138 5.4%
  9. 8x ash loop with file I/O 15,964,604 7.3%
  10. final marker 680 0%
state breakdown label P114 PTW-owner workload cycles 218,442,605 cpi 2.53
  1. fetch 3.5% 7,618,590
  2. execute 39.5% 86,273,818
  3. mem 12.8% 27,987,105
  4. walker 1.2% 2,684,438
  5. writeback 39.5% 86,249,144
  6. mul/div 3.5% 7,627,794