Result illustrating the regression of Tcl_ReadChars in absence of append (doubling of bytes in internal object used for read on every iteration), bug [da16d15574]

result.diff

diff --git "a/result-org.txt" "b/result-fix.txt"
--- "a/result-org.txt"
+++ "b/result-fix.txt"
 % # with 4KB buffersize:
 % setup   { set ch [::tclTestPerf-Chan::_get_test_chan 4096]; fconfigure $ch -buffersize }
 4096
 % # 10 * 1M:
 % read $ch [expr {int(1e6)}]
-6757.00 µs/# 10 # 147.99 #/sec 67.570 net-ms
+36189.9 µs/# 10 # 27.632 #/sec 361.899 net-ms
 
 % # 10 * 2M:
 % read $ch [expr {int(2e6)}]
-7606.70 µs/# 10 # 131.46 #/sec 76.067 net-ms
+142283.9 µs/# 10 # 7.028 #/sec 1422.839 net-ms
 
 % # 10 * 10M:
 % read $ch [expr {int(10e6)}]
-37384.6 µs/# 10 # 26.749 #/sec 373.846 net-ms
+4194017 µs/# 10 # 0.238 #/sec 41940.175 net-ms
 
 % #  1 * 20M:
 % read $ch; break
-79803.0 µs/# 1 # 12.531 #/sec 79.803 net-ms
+16742993 µs/# 1 # 0.060 #/sec 16742.993 net-ms
 
 % cleanup { close $ch }
 
 % # with 1MB buffersize:
 % setup   { set ch [::tclTestPerf-Chan::_get_test_chan 1048576]; fconfigure $ch -buffersize }
 1048576
 % # 10 * 1M:
 % read $ch [expr {int(1e6)}]
-3701.80 µs/# 10 # 270.14 #/sec 37.018 net-ms
+5515.10 µs/# 10 # 181.32 #/sec 55.151 net-ms
 
 % # 10 * 2M:
 % read $ch [expr {int(2e6)}]
-4105.30 µs/# 10 # 243.59 #/sec 41.053 net-ms
+3510.20 µs/# 10 # 284.88 #/sec 35.102 net-ms
 
 % # 10 * 10M:
 % read $ch [expr {int(10e6)}]
-22805.0 µs/# 10 # 43.850 #/sec 228.050 net-ms
+30793.2 µs/# 10 # 32.475 #/sec 307.932 net-ms
 
 % #  1 * 20M:
 % read $ch; break
-65264.0 µs/# 1 # 15.322 #/sec 65.264 net-ms
+101003.0 µs/# 1 # 9.901 #/sec 101.003 net-ms
 
 % cleanup { close $ch }
 
 ********************************************************************************
-Total 8 cases in 1.04 sec. (0.97 net-sec.):
-227427.400000 µs/# 62 # 64.005 #/sec 968.671 net-ms
+Total 8 cases in 60.99 sec. (60.97 net-sec.):
+21256305.300000 µs/# 62 # 1.017 #/sec 60967.094 net-ms
 Average:
-28428.425000 µs/# 7 # 58 #/sec 121.084 net-ms
+2657038.162500 µs/# 7 # 1 #/sec 7620.887 net-ms
 Min:
-3701.80 µs/# 10 # 270.14 #/sec 37.018 net-ms
+3510.20 µs/# 10 # 284.88 #/sec 35.102 net-ms
 Max:
-79803.0 µs/# 1 # 12.531 #/sec 79.803 net-ms
+16742993 µs/# 1 # 0.060 #/sec 16742.993 net-ms
 ********************************************************************************