Get back to the original performance number by tweaking the flushable logic to just avoid the negative value:
Get back to the original performance number by tweaking the flushable logic to just avoid the negative value:

zhihui@yuzu: /zzh-slash2/zhihui$ time dd if=/dev/zero of=biggie19.dat bs=1M count=102400
102400+0 records in
102400+0 records out
107374182400 bytes (107 GB) copied, 913.41 s, 118 MB/s

real	15m13.414s
user	0m0.126s
sys	0m15.873s

zhihui@yuzu: /zzh-slash2/zhihui$ time dd if=biggie18.dat of=/dev/null bs=1M count=102400
102400+0 records in
102400+0 records out
107374182400 bytes (107 GB) copied, 1189.09 s, 90.3 MB/s

real	19m49.092s
user	0m0.153s
sys	0m4.515s

With pipe size of 256 instead of default of 128:

zhihui@yuzu: /zzh-slash2/zhihui$ time dd if=biggie19.dat of=/dev/null bs=1M count=102400
102400+0 records in
102400+0 records out
107374182400 bytes (107 GB) copied, 935.012 s, 115 MB/s

real	15m35.015s
user	0m0.125s
sys	0m4.734s



git-svn-id: ae92b08b608af1c8cefa3e10d2325ea527204e07@25459 3eda493b-6a19-0410-b2e0-ec8ea4dd8fda

pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable