Skip to content

Correction: memory_ops for encoder_forward #797

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
MasterSkepticista wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Correction: memory_ops for encoder_forward #797

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 5 additions & 4 deletions dev/cuda/encoder_forward.cu
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -237,10 +237,11 @@ int main(int argc, char **argv) {
kernel_num, d_out, d_inp, d_wte, d_wpe, B, T, C, block_size
);

// napkin math: estimate the memory bandwidth achieved
// for each (B,T,C) output element, we do 3 reads and 1 write, 4 bytes each
// and e.g. A100 40GB PCIe is advertised at 1,555GB/s
long memory_ops = B * T * C * 4 * 4;
// Estimate memory bandwidth achieved: Total memory_ops * bytes per value.
// * Read one inp token (B, T), one wte float (B, T, C), one wpe float (B, T, C)
// * Write one out float (B, T, C)
// Total = (1 + 3C) ops, 2 bytes each (4 bytes if f32)
long memory_ops = B * T * (1 + 3 * C) * sizeof(floatX);
float memory_bandwidth = memory_ops / elapsed_time / 1e6;

printf("block_size %4d | time %.4f ms | bandwidth %.2f GB/s\n", block_size, elapsed_time, memory_bandwidth);
Expand Down