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added max_fanout=10 to asap7/cva6 and added SKIP_CRIT_VT_SWAP option #3512

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Merged
maliberty merged 3 commits into from
Sep 26, 2025
Merged

added max_fanout=10 to asap7/cva6 and added SKIP_CRIT_VT_SWAP option #3512

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8c7b33e
added max_fanout=10 to asap7/cva6 and added SKIP_CRIT_VT_SWAP option
precisionmoon Sep 23, 2025
7c34076
FlowVariables.md
precisionmoon Sep 24, 2025
493c779
another flow doc fix
precisionmoon Sep 24, 2025
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4 changes: 4 additions & 0 deletions docs/user/FlowVariables.md
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Expand Up @@ -216,6 +216,7 @@ configuration file.
| <a name="SETUP_REPAIR_SEQUENCE"></a>SETUP_REPAIR_SEQUENCE| Specifies the sequence of moves to do in repair_timing -setup. This should be a string of move keywords separated by commas such as the default when not used: "unbuffer,sizedown,sizeup,swap,buffer,clone,split".| |
| <a name="SETUP_SLACK_MARGIN"></a>SETUP_SLACK_MARGIN| Specifies a time margin for the slack when fixing setup violations. This option allows you to overfix or underfix(negative value, terminate retiming before 0 or positive slack). See HOLD_SLACK_MARGIN for more details.| 0|
| <a name="SET_RC_TCL"></a>SET_RC_TCL| Metal & Via RC definition file path.| |
| <a name="SKIP_CRIT_VT_SWAP"></a>SKIP_CRIT_VT_SWAP| Do not perform VT swap on critical cells to improve QoR (default: do critical VT swap). This is an additional VT swap on critical cells that remain near the end of setup fixing. If SKIP_VT_SWAP is set to 1, this also disables critical cell VT swap.| |
| <a name="SKIP_CTS_REPAIR_TIMING"></a>SKIP_CTS_REPAIR_TIMING| Skipping CTS repair, which can take a long time, can be useful in architectural exploration or when getting CI up and running.| |
| <a name="SKIP_DETAILED_ROUTE"></a>SKIP_DETAILED_ROUTE| Skips detailed route.| 0|
| <a name="SKIP_GATE_CLONING"></a>SKIP_GATE_CLONING| Do not use gate cloning transform to fix timing violations (default: use gate cloning).| |
Expand Down Expand Up @@ -335,6 +336,7 @@ configuration file.
- [RTLMP_WIRELENGTH_WT](#RTLMP_WIRELENGTH_WT)
- [SETUP_REPAIR_SEQUENCE](#SETUP_REPAIR_SEQUENCE)
- [SETUP_SLACK_MARGIN](#SETUP_SLACK_MARGIN)
- [SKIP_CRIT_VT_SWAP](#SKIP_CRIT_VT_SWAP)
- [SKIP_GATE_CLONING](#SKIP_GATE_CLONING)
- [SKIP_LAST_GASP](#SKIP_LAST_GASP)
- [SKIP_PIN_SWAP](#SKIP_PIN_SWAP)
Expand Down Expand Up @@ -385,6 +387,7 @@ configuration file.
- [REPORT_CLOCK_SKEW](#REPORT_CLOCK_SKEW)
- [SETUP_REPAIR_SEQUENCE](#SETUP_REPAIR_SEQUENCE)
- [SETUP_SLACK_MARGIN](#SETUP_SLACK_MARGIN)
- [SKIP_CRIT_VT_SWAP](#SKIP_CRIT_VT_SWAP)
- [SKIP_CTS_REPAIR_TIMING](#SKIP_CTS_REPAIR_TIMING)
- [SKIP_GATE_CLONING](#SKIP_GATE_CLONING)
- [SKIP_LAST_GASP](#SKIP_LAST_GASP)
Expand All @@ -407,6 +410,7 @@ configuration file.
- [ROUTING_LAYER_ADJUSTMENT](#ROUTING_LAYER_ADJUSTMENT)
- [SETUP_REPAIR_SEQUENCE](#SETUP_REPAIR_SEQUENCE)
- [SETUP_SLACK_MARGIN](#SETUP_SLACK_MARGIN)
- [SKIP_CRIT_VT_SWAP](#SKIP_CRIT_VT_SWAP)
- [SKIP_GATE_CLONING](#SKIP_GATE_CLONING)
- [SKIP_INCREMENTAL_REPAIR](#SKIP_INCREMENTAL_REPAIR)
- [SKIP_LAST_GASP](#SKIP_LAST_GASP)
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2 changes: 1 addition & 1 deletion flow/designs/asap7/cva6/config.mk
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Expand Up @@ -95,7 +95,7 @@ export PLACE_DENSITY = 0.69

# a smoketest for this option, there are a
# few last gasp iterations
export SKIP_LAST_GASP ?= 1
#export SKIP_LAST_GASP ?= 1

# For use with SYNTH_HIERARCHICAL
export SYNTH_MINIMUM_KEEP_SIZE ?= 40000
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1 change: 1 addition & 0 deletions flow/designs/asap7/cva6/constraint.sdc
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Expand Up @@ -34,3 +34,4 @@ create_clock [get_ports $clk_port] -name $clk_name -period $clk_period


set_false_path -to [get_ports {rvfi_probes_o}]
set_max_fanout 10 [current_design]
1 change: 1 addition & 0 deletions flow/scripts/util.tcl
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Expand Up @@ -26,6 +26,7 @@ proc repair_timing_helper { args } {
append_env_var additional_args SKIP_BUFFER_REMOVAL -skip_buffer_removal 0
append_env_var additional_args SKIP_LAST_GASP -skip_last_gasp 0
append_env_var additional_args SKIP_VT_SWAP -skip_vt_swap 0
append_env_var additional_args SKIP_CRIT_VT_SWAP -skip_crit_vt_swap 0
append_env_var additional_args MATCH_CELL_FOOTPRINT -match_cell_footprint 0
log_cmd repair_timing {*}$additional_args
}
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9 changes: 9 additions & 0 deletions flow/scripts/variables.yaml
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Expand Up @@ -577,6 +577,15 @@ SKIP_VT_SWAP:
- cts
- floorplan
- grt
SKIP_CRIT_VT_SWAP:
description: >
Do not perform VT swap on critical cells to improve QoR (default: do critical VT swap).
This is an additional VT swap on critical cells that remain near the end of setup fixing.
If SKIP_VT_SWAP is set to 1, this also disables critical cell VT swap.
stages:
- cts
- floorplan
- grt
REMOVE_CELLS_FOR_EQY:
description: >
String patterns directly passed to write_verilog -remove_cells <> for
Expand Down