Messages in this thread | | | Subject | Re: [PATCH] Win32 equivalent to GetTickCount systemcall (i386) | From | Arjan van de Ven <> | Date | Tue, 06 Dec 2005 12:35:17 +0100 |
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On Tue, 2005-12-06 at 12:23 +0100, David Engraf wrote: > > On Tue, 2005-12-06 at 11:36 +0100, David Engraf wrote: > > > This patch adds a new systemcall on i386 architectures returning the > jiffies > > > value to the application. > > > As a kernel developer you can use jiffies but from the user space there > is > > > no equivalent function which counts every millisecond like the Win32 > > > GetTickCount. > > > a few comments > > > 1) jiffies are 64 bit not 32 > > Jiffies is defined as "unsigned long volatile __jiffy_data jiffies". On i386 > machines unsigned long is 32.
but it's a subvariable of jiffies64 which is 64 bit > > > > 2) jiffies are not a constant time, eg HZ is a config option, > > exposing that internal counter to userspace sounds wrong, after > > all what would it be used for > > Right, HZ is defined as USER_HZ which can be set over the config. On normal > desktop systems it should be 1000 on other machines it could also be 100 or > 250. Either we can ignore the setting and the function depends on the > USER_HZ config, or we have to calculate the right value with USER_HZ.
but then.. why?
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