Hi, Can i use Peterson Lock as SMP Lock, if the processor doesn't support Get-and-Set instruction? Thanks, Mani
Can i use Peterson Lock as SMP lock??
Wed, 08/18/2010 - 03:11
Can i use Peterson Lock as SMP lock??
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Wed, 08/18/2010 - 03:18
Yes, of course. However, then hardware has to support either sequentially-consistent memory model or #StoreLoad style memory fences.
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Wed, 08/18/2010 - 07:33
Peterson's lock was designed for precisely this scenario. However, you need to ensure that the operations become visible to the other processors in the right order. The algorithm assumes a sequentially-consistent memory model, and on some platforms this will require memory fence operations before and/or after some of the stores and loads.
You also need to bear in mind that Peterson's lock is not a replacement for a general-purpose mutex --- each thread that tries to access the critical section must have a specific ID. The basic algorithm only works with 2 specific threads, though it is possible to extend it to more.
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Fri, 08/20/2010 - 05:45
Hi, thanks for the reply. But how can we extend Peterson lock for N-processes? Thanks, Mani
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Tue, 08/31/2010 - 19:01
This paper describes a technique to convert two-wayPeterson'slock into N-way:
http://www.google.com/url?sa=t&source=web&cd=10&ved=0CDcQFjAJ&url=http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.86.9087%26rep%3Drep1%26type%3Dpdf&ei=SLN9TMjvIIKnnQebi_H3AQ&usg=AFQjCNHYzNkfxUJVNVbe1-lDHV5LKOeheQ I think they call it a filter lock or something...