Merge pull request #2060 from verilog-to-routing/terminate_if_timing_fails

Terminate if timing fails

Author: vaughnbetz

doc/src/vpr/command_line_usage.rst

@@ -283,6 +283,12 @@ General Options
     .. warning:: Exercise extreme caution when turning this option off -- be sure you completely understand why the issue is being flagged, and why it is OK to treat as a warning instead of an error.
 
     **Default:** ``on``
+    
+.. option:: --terminate_if_timing_fails {on, off}
+
+    Controls whether VPR should terminate if timing is not met after routing. 
+    
+    **Default:** ``off``
 
 .. _filename_options:
 

vpr/src/base/read_options.cpp

@@ -1475,6 +1475,12 @@ argparse::ArgumentParser create_arg_parser(std::string prog_name, t_options& arg
         .default_value("off")
         .show_in(argparse::ShowIn::HELP_ONLY);
 
+    gen_grp.add_argument<bool, ParseOnOff>(args.terminate_if_timing_fails, "--terminate_if_timing_fails")
+        .help(
+            "During final timing analysis after routing, if a negative slack anywhere is returned and this option is set, \n"
+            "VPR_FATAL_ERROR is called and processing ends.")
+        .default_value("off");
+
     auto& file_grp = parser.add_argument_group("file options");
 
     file_grp.add_argument<e_arch_format, ParseArchFormat>(args.arch_format, "--arch_format")

vpr/src/base/read_options.h

@@ -69,6 +69,7 @@ struct t_options {
     argparse::ArgValue<std::string> disable_errors;
     argparse::ArgValue<std::string> suppress_warnings;
     argparse::ArgValue<bool> allow_dangling_combinational_nodes;
+    argparse::ArgValue<bool> terminate_if_timing_fails;
 
     /* Atom netlist options */
     argparse::ArgValue<bool> absorb_buffer_luts;

vpr/src/base/vpr_api.cpp

@@ -73,6 +73,7 @@
 #include "vpr_constraints_reader.h"
 #include "place_constraints.h"
 #include "place_util.h"
+#include "timing_fail_error.h"
 
 #include "vpr_constraints_writer.h"
 
@@ -342,6 +343,9 @@ void vpr_init_with_options(const t_options* options, t_vpr_setup* vpr_setup, t_a
             vtr::ScopedStartFinishTimer t("Load Timing Constraints");
             timing_ctx.constraints = read_sdc(vpr_setup->Timing, atom_ctx.nlist, atom_ctx.lookup, *timing_ctx.graph);
         }
+        {
+            set_terminate_if_timing_fails(options->terminate_if_timing_fails);
+        }
     }
 
     //Initialize vpr floorplanning constraints

vpr/src/base/vpr_context.h

@@ -113,6 +113,9 @@ struct TimingContext : public Context {
     std::shared_ptr<tatum::TimingConstraints> constraints;
 
     t_timing_analysis_profile_info stats;
+
+    /* Represents whether or not VPR should fail if timing constraints aren't met. */
+    bool terminate_if_timing_fails = false;
 };
 
 namespace std {

vpr/src/timing/timing_fail_error.cpp

@@ -0,0 +1,18 @@
+#include <fstream>
+#include <sstream>
+
+#include "vtr_log.h"
+#include "vtr_assert.h"
+#include "vtr_math.h"
+
+#include "globals.h"
+#include "timing_util.h"
+#include "timing_fail_error.h"
+
+/* Sets terminate_if_timing_fails in the timing context if the user has indicated
+ * terminate_if_timing_fails option should be on.
+ */
+void set_terminate_if_timing_fails(bool cmd_opt_terminate_if_timing_fails) {
+    auto& timing_ctx = g_vpr_ctx.mutable_timing();
+    timing_ctx.terminate_if_timing_fails = cmd_opt_terminate_if_timing_fails;
+}

vpr/src/timing/timing_fail_error.h

@@ -0,0 +1,13 @@
+#ifndef VPR_FAIL_ERROR_H
+#define VPR_FAIL_ERROR_H
+#include <memory>
+
+#include "timing_info_fwd.h"
+#include "tatum/analyzer_factory.hpp"
+#include "tatum/timing_paths.hpp"
+#include "timing_util.h"
+
+/* Represents whether or not VPR should fail if timing constraints aren't met. */
+void set_terminate_if_timing_fails(bool cmd_opt_terminate_if_timing_fails);
+
+#endif

vpr/src/timing/timing_util.cpp

@@ -8,6 +8,7 @@
 #include "globals.h"
 #include "timing_util.h"
 #include "timing_info.h"
+#include "timing_fail_error.h"
 
 double sec_to_nanosec(double seconds) {
     return 1e9 * seconds;
@@ -415,6 +416,15 @@ void print_setup_timing_summary(const tatum::TimingConstraints& constraints,
             sec_to_mhz(fanout_weighted_geomean_intra_domain_cpd));
 
     VTR_LOG("\n");
+
+    /* If the terminate_if_timing fails option is on, this checks if slack is negative and if user wants VPR
+     * flow to fail if their design doesn't meet timing constraints. If both conditions are true, the function
+     * adds details about the negative slack to a string that will be printed when VPR throws an error.
+     */
+    if (timing_ctx.terminate_if_timing_fails && (setup_worst_neg_slack < 0 || setup_total_neg_slack < 0) && prefix == "Final ") {
+        std::string msg = "\nDesign did not meet timing constraints.\nTiming failed and terminate_if_timing_fails set -- exiting";
+        VPR_FATAL_ERROR(VPR_ERROR_TIMING, msg.c_str());
+    }
 }
 
 /*
@@ -593,8 +603,14 @@ std::vector<HistogramBucket> create_hold_slack_histogram(const tatum::HoldTiming
 }
 
 void print_hold_timing_summary(const tatum::TimingConstraints& constraints, const tatum::HoldTimingAnalyzer& hold_analyzer, std::string prefix) {
-    VTR_LOG("%shold Worst Negative Slack (hWNS): %g ns\n", prefix.c_str(), sec_to_nanosec(find_hold_worst_negative_slack(hold_analyzer)));
-    VTR_LOG("%shold Total Negative Slack (hTNS): %g ns\n", prefix.c_str(), sec_to_nanosec(find_hold_total_negative_slack(hold_analyzer)));
+    auto& timing_ctx = g_vpr_ctx.timing();
+
+    auto hold_worst_neg_slack = sec_to_nanosec(find_hold_worst_negative_slack(hold_analyzer));
+    auto hold_total_neg_slack = sec_to_nanosec(find_hold_total_negative_slack(hold_analyzer));
+
+    VTR_LOG("%shold Worst Negative Slack (hWNS): %g ns\n", prefix.c_str(), hold_worst_neg_slack);
+    VTR_LOG("%shold Total Negative Slack (hTNS): %g ns\n", prefix.c_str(), hold_total_neg_slack);
+
     /*For testing*/
     //VTR_LOG("Hold Total Negative Slack within clbs: %g ns\n", sec_to_nanosec(find_total_negative_slack_within_clb_blocks(hold_analyzer)));
     VTR_LOG("\n");
@@ -637,6 +653,15 @@ void print_hold_timing_summary(const tatum::TimingConstraints& constraints, cons
         }
     }
     VTR_LOG("\n");
+
+    /* If the terminate_if_timing fails option is on, this checks if slack is negative and if user wants VPR
+     * flow to fail if their design doesn't meet timing constraints. If both conditions are true, the function
+     * adds details about the negative slack to a string that will be printed when VPR throws an error.
+     */
+    if (timing_ctx.terminate_if_timing_fails && (hold_worst_neg_slack < 0 || hold_total_neg_slack < 0) && prefix == "Final ") {
+        std::string msg = "\nDesign did not meet timing constraints.\nTiming failed and terminate_if_timing_fails set -- exiting";
+        VPR_FATAL_ERROR(VPR_ERROR_TIMING, msg.c_str());
+    }
 }
 
 /*

vpr/src/util/vpr_utils.cpp

@@ -19,6 +19,7 @@
 #include "string.h"
 #include "pack_types.h"
 #include "device_grid.h"
+#include "timing_fail_error.h"
 
 /* This module contains subroutines that are used in several unrelated parts *
  * of VPR.  They are VPR-specific utility routines.                          */

vtr_flow/parse/pass_requirements/pass_requirements.timing_fail.txt

@@ -0,0 +1,2 @@
+vpr_status;Equal()
+error;Equal()