[[!meta copyright="Copyright © 2009, 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU Free Documentation License|/fdl]]."]]"""]] [[!tag open_issue_porting]] Neither the `time` executable from the GNU time package work completely correctly, nor does the GNU Bash built-in one. tschwinge@flubber:~ $ \time sleep 2 0.00user 0.00system 9:38:00elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps tschwinge@flubber:~ $ \time sleep 4 0.00user 0.00system 18:50:25elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps tschwinge@flubber:~ $ \time sleep 6 0.00user 0.00system 28:00:53elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps tschwinge@flubber:~ $ time sleep 2 real 0m2.093s user 0m0.000s sys 0m0.011s tschwinge@flubber:~ $ time sleep 4 real 0m4.083s user 0m0.000s sys 0m0.010s tschwinge@flubber:~ $ time sleep 6 real 0m6.164s user 0m0.000s sys 0m0.010s GNU time's *elapsed* value is off by some factor. $ \time factor 1111111111111111111 1111111111111111111: 1111111111111111111 0.00user 0.00system 52:39:24elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps $ time factor 1111111111111111111 1111111111111111111: 1111111111111111111 real 0m11.424s user 0m0.000s sys 0m0.010s As above; also here all the running time should be attriuted to *user* time. This is probably a [[!taglink open_issue_gnumach]]. # 2011-09-02 Might want to revisit this, and take Xen [[!tag open_issue_xen]] into account -- I believe flubber has already been Xenified at that time. ## IRC, freenode, #hurd, 2011-09-02 While testing some [[performance/IPC_virtual_copy]] performance issues: And I can confirm that with dd if=/dev/zero of=/dev/null bs=4k running, a parallel sleep 10 takes about 20 s (on strauss).