Need help for TLB ratio problems for my class please

[paro333]

Need help finding the following:

(for the tlb hit, I started doing (.95)(.10)+(1-.05)(?)=

I am really lost though and need help pllleaeeasee)


TLB hit and cache hit.
and also TLB miss, page table hit, cache hit,
TLB Miss, page table hit, cache miss
TLB miss, page table miss, cache hit

Following data is given
TLB Hit requires 4ns
Cache hit requires 10 ns
Memory reference requires 32 ns
disk reference requires 256 ms (includes updating page table, cache, and TLB)
TLB hit ratio is 88%
cache hit ratios is 95%
page fault ratio is .002
On a TLB or cache miss, the time required for access includes a TLB and /or cache update, but the access is not restarted
on a page fault, the page is fetched from disk, all updates are performed but the access is restarted
All references are sequential (no overlap, nothing done in parallel)

[jemidiah]

You haven't posted a question.... To be honest, you'll probably get better help from a human (i.e. your professor) one-on-one than on a forum. At the least, I bet it will be faster for them to figure out what you're missing and explain it to you.

You could also read the Wikipedia page on TLB's, or post a specific question. Good luck .

[paro333]

I need to find the following :

TLB hit and cache hit.
and also TLB miss, page table hit, cache hit,
TLB Miss, page table hit, cache miss
TLB miss, page table miss, cache hit

and there was data given that I pasted in the post before.

[jemidiah]

Again, those aren't questions. I can think of three different interpretations for the first line.

1. You might mean the amount of time it takes for a TLB hit to occur, and the amount of time for a cache hit to occur... but that's already given as 4ns and 10ns, so why would anyone ask?
2. You might want to find the expected access time presuming a TLB hit followed by a page table hit, with the next step being unknown but following the ratios given.
3. You might want to find the probability that you have a TLB hit followed by a cache hit.

I dunno. Perhaps I'm just stressed, but if you can't be bothered to write a clear question, I can't be bothered to answer it....


As a general example, though, suppose you have a cache and storage. You hit the cache 1 time in 3 for whatever data you're accessing. The cache takes 5ns, storage takes 15ns. What's the expected data recovery time overall?

1/3rd of the time it's 5ns; (1-1/3rd) = 2/3rds it's 15 ns. So, overall this is just 5ns/3 + 2*15ns/3 = 35/3 ns ~= 11.67 ns.

Perhaps that will help you....