Given Roger's comment that 64 and beyone "breaks binary compatibility"
and should only be done on a major release boundry, isn't *this* the
exact right time to do so?  The Solaris10 to OpenSolaris Enterprise
change IMO *is* such a major release point.  There won't be such an
opportunity again for decades...

   -John


On Mon, Feb 22, 2010 at 11:37 AM, Garrett D'Amore <gdamore at sun.com> wrote:
> On 02/22/10 11:28 AM, Roger A. Faulkner wrote:
>>
>> I am sponsoring this automatic case for myself.
>>
>
> +1 on the case, on the justification for not expanding to 64.
>
> IMO, this pushes the boundary of what's permissible in a self-review, but I
> see no reason to promote it to a full fast track at this point.
>
> ? ?-- Garrett
>
>> The number of realtime signals supported by Solaris is quite small (8).
>> This is the minimum number required for Posix branding.
>>
>> However, other systems provide many more.
>> Linux supports 32-64 realtime signals depending on the architecture,
>> BSD does 32 or 64 depending on architecture, AIX supports 111.
>>
>> This affects Solaris directly in that the Linux zone
>> provided by Solaris cannot support Linux applications
>> that use more than 8 realtime signals. ?See the bug report:
>> ? ? 6820733 lack of realtime signals causes Linux application
>> ? ? ? ? ? ? in BrandZ to fail
>> which is a duplicate of the more general bug report:
>> ? ? 6820737 Solaris needs to increase the number of realtime signals
>> ? ? ? ? ? ? for platform parity
>>
>> This case proposes to increase the number of realtime signals
>> supported by Solaris from 8 to 32.
>>
>> Why not just go to 64, one might ask?
>> The reason is contained in the 6820737 bug report's Evaluation:
>>
>> ? ? Now, as to the request to increase the number of real-time signals
>> ? ? to 64, this would more than double the currently supported number
>> ? ? of signals. ?The sigset_t structure, in its present definition,
>> ? ? can only support a maximum of 128 signals. ?It's a limited resource.
>> ? ? Increasing the number of real-time signals to 64 would leave only
>> ? ? 24 bits remaining in the sigset_t definition for future expansion.
>> ? ? We need more wiggle-room than that for future expansion.
>>
>> ? ? So, when the number of real-time signals is increased, it will only
>> ? ? be increased to 32, not 64. ?We can increase to 64 only by changing
>> ? ? the definition of sigset_t and this breaks binary compatibility,
>> ? ? so this can be done only when we move from Solaris 2.x to Solaris 3.x
>> ? ? (or whatever the next naming scheme will be called).
>>
>> Roger Faulkner
>>
>>
>
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