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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2015-02-18 00:58:35 +0100
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2015-02-18 00:58:35 +0100
commit49a086299e047b18280457b654790ef4a2e5abfa (patch)
treec2b29e0734d560ce4f58c6945390650b5cac8a1b /open_issues/gnumach_tick.mdwn
parente2b3602ea241cd0f6bc3db88bf055bee459028b6 (diff)
Revert "rename open_issues.mdwn to service_solahart_jakarta_selatan__082122541663.mdwn"
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+[[!meta copyright="Copyright © 2012, 2013 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_gnumach]]
+
+
+# IRC, freenode, #hurd, 2012-07-05
+
+ <pinotree> braunr: wrt to mach: it seems to me it ticks every 10ms or so,
+ it is true?
+ <braunr> yes
+ <braunr> and it's not preemptible
+
+[[microkernel/mach/gnumach/preemption]].
+
+ <pinotree> braunr: that means a gnumach kernel currently has a maximum
+ uptime of almost 500 days
+ <braunr> pinotree: what do you mean ?
+ <pinotree> there's an int (or uint, i don't remember) variable that keeps
+ the tick count
+ <braunr> yes the tick variable should probably be a 64-bits type
+ <braunr> or a struct
+ <braunr> but the tick count should only be used for computation on "short"
+ delays
+ <braunr> and it should be safe to use it even when it overflows
+ <braunr> it's not the wall clock
+ <pinotree> i found that when investigating why the maximum timeout for a
+ mach_msg is like INT_MAX >> 2 (or 4) or something like that, also due to
+ the tick count
+ <braunr> iirc, in linux, they mostly use the lower 32-bits on 32-bits
+ architecture, updating the 32 upper only when necessary