lkml.org 
[lkml]   [2006]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Introduce jiffies_32 and related compare functions
David Miller a écrit :
> From: Eric Dumazet <dada1@cosmosbay.com>
> Date: Tue, 12 Dec 2006 05:09:23 +0100
>
>> We definitly *like* being able to use bigger timeouts on 64bits platforms.
>>
>> Not that they are mandatory since the same application should run fine on
>> 32bits kernel. But as the standard type for 'tick timestamps' is 'unsigned
>> long', a change would be invasive.
>>
>> Maybe some applications are now relying on being able to
>> sleep()/select()/poll() for periods > 30 days and only run on 64
>> bits kernels.
>
> I think one possible target would be struct timer, at least
> in theory.
>
> There is also a line of reasoning that says that on 64-bit
> platforms we have some flexibility to set HZ very large, if
> we wanted to at some point, and going to 32-bit jiffies
> storage for some things may eliminate that kind of flexibility.
>

Yes good point, and my understanding is that we go for a tickless kernel in
2.6.21, or so.
I wonder if virtual HZ wont be sticked to a low value.

I suspect in the case HZ raises, we switch some/most uses of jiffies_32 to
another variable (xtime_32 or whatever), but keep the storage on 32bits...

But keeping 64bits values 'just because hardware allows us this kind of
expenditure' seems not reasonable to me, but lazy...

Eric

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-12-12 07:59    [W:0.058 / U:0.840 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site