Data Hazards in Pipelining | IIT lecture Series | Computer Organization

In the domain of central processing unit (CPU) design, hazards are problems with the instruction pipeline in CPU microarchitectures when the next instruction cannot execute in the following clock cycle,[1] and can potentially lead to incorrect computation results. Three common types of hazards are data hazards, structural hazards, and control flow hazards (branching hazards).[2]
There are several methods used to deal with hazards, including pipeline stalls/pipeline bubbling, operand forwarding, and in the case of out-of-order execution, the scoreboarding method and the Tomasulo algorithm.
Data hazards Types :
Data hazards occur when instructions that exhibit data dependence modify data in different stages of a pipeline. Ignoring potential data hazards can result in race conditions (also termed race hazards). There are three situations in which a data hazard can occur:
1. read after write (RAW), a true dependency
2. write after read (WAR), an anti-dependency
3. write after write (WAW), an output dependency
Source : en.wikipedia.o...)
HAZARDS DURING PIPELINING (Operand Forwarding Technique)
data hazards in instruction pipelining
data forwarding in pipeline
Data Dependency
branch prediction computer architecture
tomasulo algorithm
data hazards and forwarding
mips pipeline
control hazards in pipelining
structural hazards in pipelining
pipelining hazards in computer organization
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[@jenweatherwax7113]

You are a miracle! You explained in less than 8 minutes what no one else could explain in many, many hours! Thank you so much

[@honestindianpeople]

Thanks Jen hope you got what u were looking for 😊

[@BytebroUK]

Mate, over 40 years ago I started out (after a bit of Fortran IV and SEL assembly language) on 'pipelined micro-code' for a 'Floating Point Array Processor Unit', which was about the size of an upright freezer, and I believe was sold by a company called "FPS Systems", and had a whole 32,768 words (each 32-bit plus some floating point stuff) of memory, and it had a five-stage instruction pipeline. It was intellectually the most fun I've ever had.

[@alagurajan4460]

design the following set of instructions using a 5 stage instruction pipeline. if any hazards occur, identify those hazards and redesign the pipeline for rectifying each hazard. find the number of clock cycles taken to complete the following sequence of instructions. assume all stages take one clock cycle each to complete the operation. a. add r2, r1, r0 # r2 ← r0 + r1 b. mul r4, r3, r2 #r4 ← r3 + r2 c. sub r6, r5, r4 #r6 ← r5 + r4

[@tombrady7390]

in the first example after reading r1 from sub instruction we could have again read r1 value from sub only for instruction AND,OR
why agin read from starting ADD instruction.

[@sadgithendra8314]

Super explanation

[@honestindianpeople]

Thank you 🙂

[@satyajith5528]

👍

[@vickys4077]

😂👍

[@satyajith5528]

@@vickys4077 vanakamuda mapla RUclips a irunthu

[@vickys4077]

Vanakam

[@esraamohamed5601]

Thank you very much ..for all you have done !

[@piyushpandey8365]

Great explanation sir.

[@honestindianpeople]

Thanks and welcome

[@DeanRendar]

the hazard is the 3rd guy learned it wrong from 2nd guy who diverged away from 1st guy

[@honestindianpeople]

that's correct DeanRendar !!

[@atifbashir7229]

das ist super .... danke schön

[@user-kg4tt9fs1e]

great explanation sir!

[@akshatsharma9527]

Thank u Sir in depth Sesion

[@kamilia4461]

thank you so much

[@honestindianpeople]

Thanks, Kami

[@dhruvchoksi826]

At 17:07 you mentioned that when lw follows sw, there is no data hazard. But the value to be stored will be stored at the end of mem stage. While that value will be required during ID stage. If it takes garbage value in the ID stage then it gets actual value only y forwarding. So it is ultimately a memory data hazard. Please explain.

[@saoussenslii]

thank you

[@Sgoose105]

Excellent!

[@honestindianpeople]

Thanks Payton !! We are grateful that you appreciated our work

[@jenweatherwax7113]

Confused @12:15 should it be SW R1, 4(R6) ?
Instead of SW 4(R6), R1?

[@elizabethstevenson9707]

Yeah I think it’s the assembly language he used. It’s different from the normal one. Confused me a bit, too.

[@mahanteshmise6930]

I think sw syntax is wrong at 12:10. Correct me if I am wrong! Good explanation sir!

[@wennie2939]

I believe the rs and rt are flipped

[@gauravchaudhari3843]

what is abbrevation of IM and DM

[@honestindianpeople]

Instruction memory and data memory

[@gamaniprasad.n7100]

How we to learn this concept easily

[@alagurajan4460]

Sir can you solve this question?