pipe_circle_tax = 5
aborted after 20 minutes

pipe_circle_tax = 25
[mikeg]:> time ./irman
Response time measurements (milliseconds) for: 2.5.64bk5sts
      Load       Max       Min       Avg Std. Dev.
      NULL     0.362     0.009     0.010     0.002
    MEMORY   250.048     0.009     0.019     1.075
   FILE_IO   749.965     0.010     0.027     2.199
   PROCESS   824.305     0.010     0.080     2.821

real    3m20.733s
user    0m52.662s
sys     0m20.981s

pipe_circle_tax = 50
[mikeg]:> time ./irman
Response time measurements (milliseconds) for: 2.5.64bk5sts
      Load       Max       Min       Avg Std. Dev.
      NULL     0.247     0.010     0.011     0.002
    MEMORY   375.001     0.009     0.020     1.244
   FILE_IO   499.987     0.009     0.032     2.483
   PROCESS   525.932     0.010     0.051     2.306

real    3m5.857s
user    0m54.828s
sys     0m21.571s

[mikeg]:> time ./irman
Response time measurements (milliseconds) for: 2.5.64.virgin
      Load       Max       Min       Avg Std. Dev.
      NULL     0.733     0.010     0.011     0.002
    MEMORY   151.308     0.010     0.017     0.969
   FILE_IO   454.016     0.010     0.027     2.718
   PROCESS  1216.848     0.010     0.049     6.411

real    2m46.591s
user    0m20.270s
sys     0m21.622s

[mikeg]:> time ./irman
Response time measurements (milliseconds) for: 2.5.64bk5
      Load       Max       Min       Avg Std. Dev.
      NULL     3.373     0.010     0.012     0.004
    MEMORY   106.042     0.011     0.023     1.090
   FILE_IO   312.046     0.011     0.047     3.297
   PROCESS   223.482     0.010     0.037     0.488

real    2m51.265s
user    0m29.902s
sys     0m23.920s