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Thursday, September 04, 2014

These course notes are broken

'via Blog this'

Looks like course notes for a computer architecture parallel programming course.

Stupid quote: "LL, SC ... Unlike the RMW instructions, there is no need to lock the bus, yet it implements an atomic operation".

Apparently does not know that most advanced microprocessors have not "locked the bus" to implement atomic RMW instructions for decades.

Also does not know that a smart implementation of an atomic RMW is guaranteed to make forward progress - at ;east, the RMW instruction itself will complete - whereas LL/SC implementations are plagued by forward progress problems.

Instruction like this is one of the big reasons parallel programming advances so slowly.

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