Skip to content
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

IPIN Cost Multiplier #2843

Merged
merged 5 commits into from
Dec 18, 2024
Merged

IPIN Cost Multiplier #2843

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
6aa8244
Merge branch 'chan_z_prefix_sum' of https://github.com/verilog-to-rou…
amin1377 Oct 30, 2024
18622c6
Merge branch 'master' of https://github.com/verilog-to-routing/vtr-ve…
amin1377 Nov 13, 2024
e99cfd4
Merge branch 'master' of https://github.com/verilog-to-routing/vtr-ve…
amin1377 Dec 13, 2024
4920c9d
[libs][rr_graph] change cost multiple from 0.95 to 0.875
amin1377 Dec 13, 2024
af02c3e
fix typo
amin1377 Dec 13, 2024
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
7 changes: 1 addition & 6 deletions libs/librrgraph/src/utils/alloc_and_load_rr_indexed_data.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -351,18 +351,13 @@ static void load_rr_indexed_data_base_costs(const RRGraphView& rr_graph,
rr_indexed_data[RRIndexedDataId(SOURCE_COST_INDEX)].base_cost = delay_normalization_fac;
rr_indexed_data[RRIndexedDataId(SINK_COST_INDEX)].base_cost = 0.;
rr_indexed_data[RRIndexedDataId(OPIN_COST_INDEX)].base_cost = delay_normalization_fac;
// If the SPEC_CPU flag is set, we need to make sure that all floating point numbers are perfectly representable in
// binary format. Thus, we changed the IPIN_COST_INDEX base cost from 0.95 to 0.875.
// The IPIN_COST_INDEX base cost is changed from 0.95 to 0.875 so it is perfectly representable in binary format (this change is made for SPEC benchmark).
// This number is perfectly representable in a binary mantissa (without round-off) so we can get the same routing result on different platforms.
// Since the router cost calculations and heap use floating point numbers, normally we get slightly different round off with different compiler settings,
// leading to different heap sorts and hence different routings.
// To make result validation for SPEC easier, we choose all router parameters to result in calculations that fit perfectly in a 24-bit binary mantissa.
// .875 = 1/2 + 1/4 + 1/8 can be perfectly represented in a binary mantissa with only the first 3 bits set.
#ifdef SPEC_CPU
rr_indexed_data[RRIndexedDataId(IPIN_COST_INDEX)].base_cost = 0.875 * delay_normalization_fac;
#else
rr_indexed_data[RRIndexedDataId(IPIN_COST_INDEX)].base_cost = 0.95 * delay_normalization_fac;
#endif

auto rr_segment_counts = count_rr_segment_types(rr_graph, rr_indexed_data);
size_t total_segments = std::accumulate(rr_segment_counts.begin(), rr_segment_counts.end(), 0u);
Expand Down
Loading