From 21078b9f534bb572eb45a08a88c5e7c4d24928db Mon Sep 17 00:00:00 2001
From: AlexandreSinger <49374526+AlexandreSinger@users.noreply.github.com>
Date: Tue, 30 Jul 2024 09:07:09 -0400
Subject: [PATCH 1/2] Revert "update fracturable LUT connectivity based on
known legal external placements"
---
vtr_flow/arch/ispd/ultrascale_ispd.xml | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/vtr_flow/arch/ispd/ultrascale_ispd.xml b/vtr_flow/arch/ispd/ultrascale_ispd.xml
index 72bb4e73023..604d69734d6 100644
--- a/vtr_flow/arch/ispd/ultrascale_ispd.xml
+++ b/vtr_flow/arch/ispd/ultrascale_ispd.xml
@@ -504,12 +504,11 @@
-
-
-
-
-
-
+
+
+
+
+
From 70c8c2c06fb1231baa18434fb69784a1c3d5ec16 Mon Sep 17 00:00:00 2001
From: AlexandreSinger
Date: Sat, 8 Jun 2024 18:17:16 -0400
Subject: [PATCH 2/2] [Route] Added astar_offset Parameter
Using an astar_offset can help better tune the ordering heuristic for
the search used to find the shortest path in the routing graph. It is
also necessary to ensure that the heuristic is an underestimate (without
setting the astar_fac to 0.0).
---
doc/src/vpr/command_line_usage.rst | 9 +++++++++
vpr/src/base/SetupVPR.cpp | 1 +
vpr/src/base/ShowSetup.cpp | 3 ++-
vpr/src/base/read_options.cpp | 8 ++++++++
vpr/src/base/read_options.h | 1 +
vpr/src/base/vpr_types.h | 3 +++
vpr/src/place/timing_place_lookup.cpp | 3 ++-
vpr/src/route/connection_router.cpp | 17 +++++++----------
vpr/src/route/connection_router_interface.h | 1 +
vpr/src/route/route_net.tpp | 1 +
vpr/src/route/router_delay_profiling.cpp | 2 ++
vpr/test/test_connection_router.cpp | 1 +
12 files changed, 38 insertions(+), 12 deletions(-)
diff --git a/doc/src/vpr/command_line_usage.rst b/doc/src/vpr/command_line_usage.rst
index 3895d071ee5..73a4a612c08 100644
--- a/doc/src/vpr/command_line_usage.rst
+++ b/doc/src/vpr/command_line_usage.rst
@@ -1306,6 +1306,15 @@ The following options are only valid when the router is in timing-driven mode (t
**Default:** ``1.2``
+.. option:: --astar_offset
+
+ Sets how aggressive the directed search used by the timing-driven router is.
+ It is a subtractive adjustment to the lookahead heuristic.
+
+ Values between 0 and 1e-9 are resonable; higher values may increase quality at the expense of run-time.
+
+ **Default:** ``0.0``
+
.. option:: --router_profiler_astar_fac
Controls the directedness of the timing-driven router's exploration when doing router delay profiling of an architecture.
diff --git a/vpr/src/base/SetupVPR.cpp b/vpr/src/base/SetupVPR.cpp
index d05f7d5d7da..fb43fe921a2 100644
--- a/vpr/src/base/SetupVPR.cpp
+++ b/vpr/src/base/SetupVPR.cpp
@@ -423,6 +423,7 @@ static void SetupRoutingArch(const t_arch& Arch,
static void SetupRouterOpts(const t_options& Options, t_router_opts* RouterOpts) {
RouterOpts->do_check_rr_graph = Options.check_rr_graph;
RouterOpts->astar_fac = Options.astar_fac;
+ RouterOpts->astar_offset = Options.astar_offset;
RouterOpts->router_profiler_astar_fac = Options.router_profiler_astar_fac;
RouterOpts->bb_factor = Options.bb_factor;
RouterOpts->criticality_exp = Options.criticality_exp;
diff --git a/vpr/src/base/ShowSetup.cpp b/vpr/src/base/ShowSetup.cpp
index 0217b93cc63..cdf51112e46 100644
--- a/vpr/src/base/ShowSetup.cpp
+++ b/vpr/src/base/ShowSetup.cpp
@@ -382,6 +382,7 @@ static void ShowRouterOpts(const t_router_opts& RouterOpts) {
if (TIMING_DRIVEN == RouterOpts.router_algorithm) {
VTR_LOG("RouterOpts.astar_fac: %f\n", RouterOpts.astar_fac);
+ VTR_LOG("RouterOpts.astar_offset: %f\n", RouterOpts.astar_offset);
VTR_LOG("RouterOpts.router_profiler_astar_fac: %f\n", RouterOpts.router_profiler_astar_fac);
VTR_LOG("RouterOpts.criticality_exp: %f\n", RouterOpts.criticality_exp);
VTR_LOG("RouterOpts.max_criticality: %f\n", RouterOpts.max_criticality);
@@ -735,4 +736,4 @@ static void ShowNocOpts(const t_noc_opts& NocOpts) {
VTR_LOG("NocOpts.noc_sat_routing_num_workers: %d\n", NocOpts.noc_sat_routing_num_workers);
VTR_LOG("NocOpts.noc_routing_algorithm: %s\n", NocOpts.noc_placement_file_name.c_str());
VTR_LOG("\n");
-}
\ No newline at end of file
+}
diff --git a/vpr/src/base/read_options.cpp b/vpr/src/base/read_options.cpp
index f14bb940b28..5d925ddcf7d 100644
--- a/vpr/src/base/read_options.cpp
+++ b/vpr/src/base/read_options.cpp
@@ -2499,6 +2499,14 @@ argparse::ArgumentParser create_arg_parser(const std::string& prog_name, t_optio
.default_value("1.2")
.show_in(argparse::ShowIn::HELP_ONLY);
+ route_timing_grp.add_argument(args.astar_offset, "--astar_offset")
+ .help(
+ "Controls the directedness of the timing-driven router's exploration."
+ " It is a subtractive adjustment to the lookahead heuristic."
+ " Values between 0 and 1e-9 are resonable; higher values may increase quality at the expense of run-time.")
+ .default_value("0.0")
+ .show_in(argparse::ShowIn::HELP_ONLY);
+
route_timing_grp.add_argument(args.router_profiler_astar_fac, "--router_profiler_astar_fac")
.help(
"Controls the directedness of the timing-driven router's exploration"
diff --git a/vpr/src/base/read_options.h b/vpr/src/base/read_options.h
index a2dcc49d244..feda94e9fa8 100644
--- a/vpr/src/base/read_options.h
+++ b/vpr/src/base/read_options.h
@@ -220,6 +220,7 @@ struct t_options {
/* Timing-driven router options only */
argparse::ArgValue astar_fac;
+ argparse::ArgValue astar_offset;
argparse::ArgValue router_profiler_astar_fac;
argparse::ArgValue max_criticality;
argparse::ArgValue criticality_exp;
diff --git a/vpr/src/base/vpr_types.h b/vpr/src/base/vpr_types.h
index fe0a8fb4658..d776cc80c07 100644
--- a/vpr/src/base/vpr_types.h
+++ b/vpr/src/base/vpr_types.h
@@ -1343,6 +1343,8 @@ struct t_placer_opts {
* an essentially breadth-first search, astar_fac = 1 is near *
* the usual astar algorithm and astar_fac > 1 are more *
* aggressive. *
+ * astar_offset: Offset that is subtracted from the lookahead (expected *
+ * future costs) in the timing-driven router. *
* max_criticality: The maximum criticality factor (from 0 to 1) any sink *
* will ever have (i.e. clip criticality to this number). *
* criticality_exp: Set criticality to (path_length(sink) / longest_path) ^ *
@@ -1431,6 +1433,7 @@ struct t_router_opts {
enum e_router_algorithm router_algorithm;
enum e_base_cost_type base_cost_type;
float astar_fac;
+ float astar_offset;
float router_profiler_astar_fac;
float max_criticality;
float criticality_exp;
diff --git a/vpr/src/place/timing_place_lookup.cpp b/vpr/src/place/timing_place_lookup.cpp
index 8c7ff526baa..638964e66d7 100644
--- a/vpr/src/place/timing_place_lookup.cpp
+++ b/vpr/src/place/timing_place_lookup.cpp
@@ -1190,7 +1190,8 @@ void OverrideDelayModel::compute_override_delay_model(
RouterDelayProfiler& route_profiler,
const t_router_opts& router_opts) {
t_router_opts router_opts2 = router_opts;
- router_opts2.astar_fac = 0.;
+ router_opts2.astar_fac = 0.f;
+ router_opts2.astar_offset = 0.f;
//Look at all the direct connections that exist, and add overrides to delay model
auto& device_ctx = g_vpr_ctx.device();
diff --git a/vpr/src/route/connection_router.cpp b/vpr/src/route/connection_router.cpp
index e071be0abbe..4074d6d283f 100644
--- a/vpr/src/route/connection_router.cpp
+++ b/vpr/src/route/connection_router.cpp
@@ -1,6 +1,7 @@
#include "connection_router.h"
-#include "rr_graph.h"
+#include
+#include "rr_graph.h"
#include "binary_heap.h"
#include "four_ary_heap.h"
#include "bucket.h"
@@ -660,8 +661,8 @@ float ConnectionRouter::compute_node_cost_using_rcv(const t_conn_cost_para
float expected_total_delay_cost;
float expected_total_cong_cost;
- float expected_total_cong = cost_params.astar_fac * expected_cong + backwards_cong;
- float expected_total_delay = cost_params.astar_fac * expected_delay + backwards_delay;
+ float expected_total_cong = expected_cong + backwards_cong;
+ float expected_total_delay = expected_delay + backwards_delay;
//If budgets specified calculate cost as described by RCV paper:
// R. Fung, V. Betz and W. Chow, "Slack Allocation and Routing to Improve FPGA Timing While
@@ -813,7 +814,7 @@ void ConnectionRouter::evaluate_timing_driven_node_costs(t_heap* to,
rr_node_arch_name(target_node, is_flat_).c_str(),
describe_rr_node(device_ctx.rr_graph, device_ctx.grid, device_ctx.rr_indexed_data, target_node, is_flat_).c_str(),
expected_cost, to->R_upstream);
- total_cost += to->backward_path_cost + cost_params.astar_fac * expected_cost;
+ total_cost += to->backward_path_cost + cost_params.astar_fac * std::max(0.f, expected_cost - cost_params.astar_offset);
}
to->cost = total_cost;
}
@@ -905,12 +906,8 @@ void ConnectionRouter::add_route_tree_node_to_heap(
if (!rcv_path_manager.is_enabled()) {
// tot_cost = backward_path_cost + cost_params.astar_fac * expected_cost;
- float tot_cost = backward_path_cost
- + cost_params.astar_fac
- * router_lookahead_.get_expected_cost(inode,
- target_node,
- cost_params,
- R_upstream);
+ float expected_cost = router_lookahead_.get_expected_cost(inode, target_node, cost_params, R_upstream);
+ float tot_cost = backward_path_cost + cost_params.astar_fac * std::max(0.f, expected_cost - cost_params.astar_offset);
VTR_LOGV_DEBUG(router_debug_, " Adding node %8d to heap from init route tree with cost %g (%s)\n",
inode,
tot_cost,
diff --git a/vpr/src/route/connection_router_interface.h b/vpr/src/route/connection_router_interface.h
index a3e2c530cdd..b732e8f839e 100644
--- a/vpr/src/route/connection_router_interface.h
+++ b/vpr/src/route/connection_router_interface.h
@@ -23,6 +23,7 @@ struct t_conn_delay_budget {
struct t_conn_cost_params {
float criticality = 1.;
float astar_fac = 1.2;
+ float astar_offset = 0.f;
float bend_cost = 1.;
float pres_fac = 1.;
const t_conn_delay_budget* delay_budget = nullptr;
diff --git a/vpr/src/route/route_net.tpp b/vpr/src/route/route_net.tpp
index e825e7fdfcc..95df1a8346e 100644
--- a/vpr/src/route/route_net.tpp
+++ b/vpr/src/route/route_net.tpp
@@ -139,6 +139,7 @@ inline NetResultFlags route_net(ConnectionRouter& router,
t_conn_delay_budget conn_delay_budget;
t_conn_cost_params cost_params;
cost_params.astar_fac = router_opts.astar_fac;
+ cost_params.astar_offset = router_opts.astar_offset;
cost_params.bend_cost = router_opts.bend_cost;
cost_params.pres_fac = pres_fac;
cost_params.delay_budget = ((budgeting_inf.if_set()) ? &conn_delay_budget : nullptr);
diff --git a/vpr/src/route/router_delay_profiling.cpp b/vpr/src/route/router_delay_profiling.cpp
index f485f308b3f..256c4fcb933 100644
--- a/vpr/src/route/router_delay_profiling.cpp
+++ b/vpr/src/route/router_delay_profiling.cpp
@@ -95,6 +95,7 @@ bool RouterDelayProfiler::calculate_delay(RRNodeId source_node,
t_conn_cost_params cost_params;
cost_params.criticality = 1.;
cost_params.astar_fac = router_opts.router_profiler_astar_fac;
+ cost_params.astar_offset = router_opts.astar_offset;
cost_params.bend_cost = router_opts.bend_cost;
route_budgets budgeting_inf(net_list_, is_flat_);
@@ -164,6 +165,7 @@ vtr::vector calculate_all_path_delays_from_rr_node(RRNodeId src
t_conn_cost_params cost_params;
cost_params.criticality = 1.;
cost_params.astar_fac = router_opts.astar_fac;
+ cost_params.astar_offset = router_opts.astar_offset;
cost_params.bend_cost = router_opts.bend_cost;
/* This function is called during placement. Thus, the flat routing option should be disabled. */
//TODO: Placement is run with is_flat=false. However, since is_flat is passed, det_routing_arch should
diff --git a/vpr/test/test_connection_router.cpp b/vpr/test/test_connection_router.cpp
index 9ac8dbdc6ef..89ffce30577 100644
--- a/vpr/test/test_connection_router.cpp
+++ b/vpr/test/test_connection_router.cpp
@@ -41,6 +41,7 @@ static float do_one_route(RRNodeId source_node,
t_conn_cost_params cost_params;
cost_params.criticality = router_opts.max_criticality;
cost_params.astar_fac = router_opts.astar_fac;
+ cost_params.astar_offset = router_opts.astar_offset;
cost_params.bend_cost = router_opts.bend_cost;
const Netlist<>& net_list = is_flat ? (const Netlist<>&)g_vpr_ctx.atom().nlist : (const Netlist<>&)g_vpr_ctx.clustering().clb_nlist;