68988 - Use MP tasks when possible for interrupts on Mac

Status: RESOLVED WONTFIX

(NSPR :: NSPR, defect, P3)

Description

[Simon Fraser [no longer active]]

The Mac implementation of interrupts currently uses a Time Manager task to do 
work every 8ms. Since the PrimeTime call is a 68k call, this incurs more overhead 
than we'd like.

An alternative is to use the MultiProcessor APIs when available (even on single 
CPU machines), since these will have a lower overhead.

Comment 1

[Simon Fraser [no longer active]]

Attachment: Initial cut at MP task implementation

Comment 2

[Simon Fraser [no longer active]]

I've attached a first cut at an MP-task implementation of interrupts for Mac. I 
make no guarantees that this is safe, and won't crash, but it seems to work for 
me, and could be used as a basis for a real implementation.

Comment 3

[Joe Francis]

how about the defered task manager?  does that have 68k overhead?  It exists even 
where the mp api's dont.

Comment 4

[Steve Dagley]

IIRC the deferred task manager is for tasks you want to perform as you leave an 
interrupt rather than an interrupt mechanism itself

Comment 5

[Kathleen :Brade]

I tried this patch and kept landing in macsbug (dsFSErr) and had to reboot my 
Mac.  I'm running OS 9.1.  I did try running other TCP/IP apps before mozilla but 
I still couldn't get past the profile picker dismissal.

Comment 6

[Wan-Teh Chang]

Simon,

Are we still going to use MP tasks?  I haven't seen any
activity on this bug.  Should I mark it "Future" or
WONTFIX?

Comment 7

[Simon Fraser [no longer active]]

We need to do some performance evalutation on this. I'd keep it on the radar for 
now. It may be a good thing to do on Mac OS X, but not so good on 9.

Comment 8

[Steve Dagley]

I don't remember if I tested this on X but I do recall it didn't work at all for 
me under 9

Comment 9

[Jo Hermans]

Since we're now only supporting Mac OS X (where we don't need the MP tasks), I
think this can be closed.

Comment 10

[Wan-Teh Chang]

Marked the bug WONTFIX.