report_clock_timing
--> Reports timing attributes of clock networks.
EXAMPLES
The following example shows a typical summary style report.
pt_shell> report_clock_timing -type summary
****************************************
Report : clock timing
-type summary
-nworst 1
...
****************************************
Clock: CK1
----------------------------------------------------------------------------
Maximum setup launch latency:
flop9/CP 3.08 rp-+
Minimum setup capture latency:
or2_3/B 1.15 fpi-+
Minimum hold launch latency:
or2_3/B 1.15 fpi-+
Maximum hold capture latency:
flop9/CP 3.08 rp-+
Maximum active transition:
or2_3/B 0.20 fpi-+
Minimum active transition:
or2_3/B 0.09 fpi-+
Maximum setup skew:
flop9/CP rp-+
flop10/CP 0.87 rp-+
Maximum hold skew:
flop9/CP rp-+
flop10/CP -0.21 rp-+
----------------------------------------------------------------------------
The following example displays the five worst setup skews in the clock network of CLK1, taking uncertainty into account.
pt_shell> report_clock_timing -clock CLK1 -type skew -setup \
-nworst 5 -include_uncertainty_in_skew
****************************************
Report : clock timing
-type skew
-nworst 5
-setup
-include_uncertainty_in_skew
Design : multi_domain
...
****************************************
Clock: CLK1
Clock Pin Latency Uncert Skew
----------------------------------------------------------------------------
f2_2/CP 6.11 rp-+
f2_1/CP 2.01 0.11 4.21 fp-+
l3_2/G 4.10 rpi-
f1_2/CP 1.00 0.22 3.32 rpi-+
l2_2/G 4.11 rp-
f1_2/CP 1.00 0.12 3.23 rpi-+
f2_2/CP 6.11 rp-+
l3_3/G 3.01 0.11 3.21 rp-
l1_3/G 5.11 rp-
f2_1/CP 2.01 0.11 3.21 fp-+
----------------------------------------------------------------------------
The following displays the five worst launching latencies for hold paths in the clock network of CLK2.
pt_shell> report_clock_timing -clock CLK2 -hold -launch -nworst 5 \
-type latency
****************************************
Report : clock timing
-type latency
-launch
-nworst 5
-hold
Design : multi_domain
...
****************************************
Clock: CLK2
--- Latency ---
Clock Pin Trans Source Network Total
----------------------------------------------------------------------------
f1_2/CP 0.04 0.00 1.00 1.00 rpi-+
f1_3/CP 0.00 0.01 1.00 1.01 fp-+
f2_1/CP 0.01 0.01 2.00 2.01 rp-+
f1_1/CP 0.00 0.00 3.00 3.00 rpi-+
f3_2/CP 0.00 0.00 3.00 3.00 fpi-+
----------------------------------------------------------------------------
The following example demonstrates how to request a verbose report showing the worst local skew from f2_2/CP to any other sink pin.
pt_shell> report_clock_timing -type skew -verbose -from f2_2/CP
****************************************
Report : clock timing
-type skew
-verbose
-nworst 1
-setup
Design : multi_domain
...
****************************************
Clock: CLK1
Startpoint: f2_2 (rising edge-triggered flip-flop clocked by CLK1)
Endpoint: f2_1 (rising edge-triggered flip-flop clocked by CLK1)
Point Trans Incr Path
------------------------------------------------------------------
clock source latency 0.11 0.11
clk2 (in) 0.00 0.00 0.11 r
az_1/Z (B1I) 0.09 1.00 H 1.11 r
az_2/Z (B1I) 0.13 1.00 H 2.11 r
bf2_2_1/Z (B1I) 0.02 1.00 H 3.11 r
if2_2_1/Z (IVA) 0.44 1.00 H 4.11 f
bf2_2_2/Z (B1I) 0.01 1.00 H 5.11 f
if2_2_2/Z (IVA) 0.13 1.00 H 6.11 r
f2_2/CP (FD1) 0.13 0.00 6.11 r
startpoint clock latency 6.11
clock source latency 0.01 0.01
clk2 (in) 0.00 0.00 0.01 r
az_1/Z (B1I) 0.02 1.00 H 1.01 r
az_3/Z (B1I) 0.01 1.00 H 2.01 r
f2_1/CP (FD1) 0.01 0.00 2.01 r
endpoint clock latency 2.01
------------------------------------------------------------------
startpoint clock latency 6.11
endpoint clock latency -2.01
------------------------------------------------------------------
skew 4.10
The following example traces the two worst launch latencies for hold paths in the clock network of CLK1.
pt_shell> report_clock_timing -type latency -hold -verbose \
-nworst 2 -clock CLK1
****************************************
Report : clock timing
-type latency
-verbose
-launch
-nworst 2
-hold
Design : multi_domain
...
****************************************
Clock: CLK1
Endpoint: f1_2 (rising edge-triggered flip-flop clocked by CLK1')
Point Trans Incr Path
------------------------------------------------------------------
clock source latency 0.00 0.00
clk1 (in) 0.00 0.00 0.00 f
if1_2_1/Z (IVA) 0.04 1.00 H 1.00 r
f1_2/CP (FD1) 0.04 0.00 1.00 r
total clock latency 1.00
Endpoint: f1_3 (rising edge-triggered flip-flop clocked by CLK1)
Point Trans Incr Path
------------------------------------------------------------------
clock source latency 0.01 0.01
clk1 (in) 0.00 0.00 0.01 r
bf1_3_1/Z (B1I) 0.00 1.00 H 1.01 r
f1_3/CP (FD1) 0.00 0.00 1.01 r
total clock latency 1.01
The following example makes use of a slack filter to display the worst three skews between latches whose latch-to-latch paths are violating.
pt_shell> report_clock_timing -type skew -nworst 3 \
-slack_lesser_than 0.0
****************************************
Report : clock timing
-type skew
-slack_lesser_than 0.00
-nworst 3
-setup
Design : multi_domain
...
****************************************
Clock: CLKA
Clock Pin Latency CRP Skew Slack
----------------------------------------------------------------------------
f2_2/CP 6.01 rp-+
f2_1/CP 2.11 -0.03 3.87 -1.49 rp-+
l2_2/G 4.01 rp-
f1_2/CP 1.10 -0.21 2.70 -6.64 rpi-+
l1_3/G 5.01 rp-
f2_1/CP 2.11 -0.32 2.58 -1.63 rp-+
----------------------------------------------------------------------------
The following example requests the two largest setup skews for paths both launched and captured by any clock networks in the list $my_clocks.
pt_shell> report_clock_timing -type interclock_skew \
-from_clock $my_clocks -to_clock $my_clocks \
-nworst 2 -include_uncertainty_in_skew -show_clocks
****************************************
Report : clock timing
-type interclock_skew
-nworst 2
-setup
-include_uncertainty_in_skew
-show_clocks
...
****************************************
Number of startpoint pins : 907
Number of endpoint pins : 907
Number of startpoint clocks : 5
Number of endpoint clocks : 5
Clock Pin Latency Uncert Skew
----------------------------------------------------------------------------
orig_clk
orig_if/ram_pdp1/FFB35/CK 1016.72 rp-+
dcd_ram/ram_clk
dcd_ram/dcd_ram/RAM/CKRB 149.60 195.00 1062.12 rp-+
comp_clk
comp_if/c_port_if/edge_trig_reg/CK 1400.42 rp-+
comp_clk
comp_if/c_port_if/posi/iq_reg/CK 1159.09 199.00 440.34 rp-+
----------------------------------------------------------------------------
The following reports the largest two setup skews in the domain of CLKB in the context of a detailed variation-aware clock analysis, and requests the augmentation of the report with variation information.
pt_shell> report_clock_timing -type skew -clock CLKB -variation
****************************************
Report : clock timing
-type skew
-nworst 2
-variation
Design : multi_domain
...
****************************************
Clock: CLKB
--- Skew ---
Clock Pin Latency Stddev Mean Quant
----------------------------------------------------------------------------
f2_2/CP 0.40221 rp-+
f2_1/CP 0.13533 0.02825 0.26688 0.34732 rp-+
l2_1/CP 0.33036 rpi-+
l2_2/CP 0.18638 0.02626 0.14398 0.20948 rp-+
----------------------------------------------------------------------------
report_clock_timing
NAME
report_clock_timing
Reports timing attributes of clock networks.
SYNTAX
string report_clock_timing -type report_type [-clock clock_list] [-from_clock from_clock_list] [-to_clock to_clock_list] [-from from_list] [-to to_list] [-setup | -hold] [-launch | -capture] [-rise | -fall] [-nworst worst_entries] [-greater_than lower_limit] [-lesser_than upper_limit] [-slack_lesser_than slack_upper_limit] [-include_uncertainty_in_skew] [-verbose] [-significant_digits digits] [-show_clocks] [-crosstalk_delta] [-derate] [-variation] [-sort_by sort_attr] [-clock_crossing] [-include_clock_gating] [-nosplit] [-pre_commands pre_command_string] [-post_commands post_command_string]
Data Types
report_type string clock_list list from_clock_list list to_clock_list list from_list list to_list list worst_entries int lower_limit float upper_limit float slack_upper_limit float digits int sort_attr string pre_command_string string post_command_string string
ARGUMENTS
-type report_type
Specifies the type of report to be generated. You can specify the following values for report_type:
- transition - Transition time report.
- latency - Latency report.
- skew - Skew report. You cannot use the -launch, -capture, -rise, -fall, and -lesser_than options if you specify a skew report, and you can use the -include_uncertainty_in_skew option only in a skew, interclock_skew, or summary report.
- interclock_skew - Interclock skew report. You cannot use the -launch, -capture, -rise, -fall, and -lesser_than options if you specify an interclock skew report, and you can use the -include_uncertainty_in_skew option only in a skew, interclock_skew or summary report.
- summary - Summary report, which shows the worst instances of transition time, latency and skew over the clock networks or subnetworks of interest. If you specify a summary report, you can use only the -clock, -to_list, -from_list, -include_uncertainty_in_skew, -nosplit, and -significant_digits options.
For nonsummary reports, report entries are ordered with respect to the specified attribute of interest (transition time, latency, or skew). Note that all skews reported are "local" skews. For an explanation of local skew, see the DESCRIPTION section.
-clock clock_list
Uses the specified clock networks in the report. A subreport is typically produced for every clock in the clock_list, unless you additionally specify the to_list, from_list, or both options that has no network intersection with a given clock. In that case, PrimeTime drops these clocks from the clock_list and also issues a warning. By default, if you do not specify clock_list, all clocks in the design that have associated clock networks are used in the report.
-from_clock from_clock_list
Uses the specified clock networks as from-clocks in the current interclock skew report. This option can be used only in an interclock skew report. The report typically considers every clock in from_clock_list, unless you additionally specify the from_list option that has no network intersection with a given clock. In that case, PrimeTime drops these clocks from the from_clock_list and also issues a warning. By default, if you do not specify the from_clock_list option, all clocks in the design that have associated clock networks are used as from-clocks in the report.
-to_clock to_clock_list
Uses the specified clock networks as to-clocks in the current interclock skew report. This option can be used only in an interclock skew report. The report typically considers every clock in to_clock_list, unless you additionally specify a to_list that has no network intersection with a given clock. In that case, PrimeTime drops these clocks from the to_clock_list and also issues a warning. By default, if you do not specify the to_clock_list option, all clocks in the design that have associated clock networks are used as to-clocks in the report.
-from from_list
Considers the specified sequential clock network pins or ports as from-pins in the current report. If any named pin is not the clock pin of a sequential device, PrimeTime replaces that pin with all sequential clock pins in the transitive fanout of the named pin. If there are no sequential clock pins in the pin's transitive fanout, the pin is dropped from the list and a warning message is issued.
-to to_list
Considers the specified sequential clock network pins or ports as to-pins in the current report. If any named pin is not the clock pin of a sequential device, such as a sink pin, PrimeTime replaces that pin with all sequential clock pins in the transitive fanout of the named pin. If there are no sequential clock pins in the pin's transitive fanout, the pin is dropped from the list with a warning message.
For skew reports, the from-to skew sense is defined by the pins in the from_list and to_list options respectively; if the to_list option is not specified, by default all sink pins in the given clock networks are used. Thus, specifying the to_list option reduces the topological scope of the report. For transition time and latency reports, the from_list and to_list options are concatenated and treated as a single list; if neither is specified, the to_list option is assumed to be populated with all sink pins in the given clock networks.
For skew reports, the from-to skew sense is defined by the pins in the from_list and to_list options respectively; if the from_list option is not specified, by default all sink pins in the given clock networks are used. Thus, specifying the to_list option reduces the topological scope of the report. For transition time and latency reports, the from_list and to_list options are concatenated and treated as a single list; if neither is specified, the to_list option is assumed to be populated with all sink pins in the given clock networks.
For skew reports, the from-to skew sense is defined by the pins in the from_list and to_list options respectively; if the to_list option is not specified, by default all sink pins in the given clock networks are used. Thus, specifying the to_list option reduces the topological scope of the report. For transition time and latency reports, the from_list and to_list options are concatenated and treated as a single list; if neither is specified, the to_list option is assumed to be populated with all sink pins in the given clock networks.
For skew reports, the from-to skew sense is defined by the pins in the from_list and to_list options respectively; if the from_list option is not specified, by default all sink pins in the given clock networks are used. Thus, specifying the to_list option reduces the topological scope of the report. For transition time and latency reports, the from_list and to_list options are concatenated and treated as a single list; if neither is specified, the to_list option is assumed to be populated with all sink pins in the given clock networks.
-setup
Uses only the setup data path is to be used in the report. Also, the skews, latencies or transition times reported must correspond to those used by the report_timingcommand in the verification of setup constraints. The -setup and -hold options are mutually exclusive. If neither option is specified, the -setup option is assumed. You cannot use this option in summary reports.
-hold
Uses only the hold data path in the report. Also, the skews, latencies, or transition times reported must correspond to those used by the report_timing command in the verification of hold constraints. The -setup and -hold options are mutually exclusive. If neither option is specified, the -setup option is assumed. You cannot use this option in summary reports.
-launch
Uses only pins that launch data in the report. Also, latencies or transition times reported must correspond to those used by the report_timing command for sequential device clock pins that are launching data. In skew reports, the role is implicit from the from-to sense indicated by the from_list and to_list arguments. In all other reports, the -launch and -capture options are mutually exclusive. If neither option is specified, the -launch option is assumed. You cannot use this option in summary or skew reports.
-capture
Uses only pins that capture data in the report. Also, the latencies or transition times reported must correspond to those used by the report_timing command for sequential device clock pins that are capturing data. In skew reports, the role is implicit from the from-to sense indicated by the from_list and to_list options. In all other reports, the -launch and -capture options are mutually exclusive. If neither option is specified, the -launch option is assumed. You cannot use this option in summary or skew reports.
-rise
Specifies that the active transition is a rising edge for sequential device clock pins in the current report. The -rise and -fall options are mutually exclusive; if neither option is specified, the active transition at a latch or flip-flop is deduced from the launch or capture role and the behavior of the sequential device itself. This option enables you to answer "what if" questions regarding latency and transition time at sequential device clock pins. You cannot use this option in summary or skew reports.
-fall
Specifies that the active transition is a falling edge for sequential device clock pins in the current report. -rise and -fall are mutually exclusive; if neither is specified, the active transition at a latch or flip-flop is deduced from the launch or capture role and the behavior of the sequential device itself. This option enables you to answer "what if" questions regarding latency and transition time at sequential device clock pins. You cannot use this option in summary or skew reports.
-nworst worst_entries
Specifies the number of worst report entries to be reported per clock domain; the default is 1. Entries are sorted with respect to the attribute of interest (transition time, latency or skew) specified with the -type option of the report_type command.
The worst entries are those most likely to cause a violation. For example, if you request a latency report using -setup and -capture, the smallest worst_entries are listed, sorted in ascending order, because small capture latencies for setup paths are more likely to lead to a violation than large capture latencies. By contrast, for skew reports, the worst entries always correspond to the largest skews over the specified domain. You cannot use this option in summary reports.
The worst entries are those most likely to cause a violation. For example, if you request a latency report using -setup and -capture, the smallest worst_entries are listed, sorted in ascending order, because small capture latencies for setup paths are more likely to lead to a violation than large capture latencies. By contrast, for skew reports, the worst entries always correspond to the largest skews over the specified domain. You cannot use this option in summary reports.
-greater_than lower_limit
Shows only those entries with an attribute value (latency, transition time or skew) greater (more positive) than lower_limit. You cannot use this option in summary reports.
-lesser_than upper_limit
Shows only those entries with an attribute value (latency, transition time or skew) less (more negative) than upper_limit. You cannot use this option in summary or skew reports.
-slack_lesser_than slack_upper_limit
Shows only those entries with a slack value less (more negative) than slack_upper_limit. For skew report entries slack is the worst slack over all paths launched by the from-pin and captured by the to-pin. For transition time or latency report entries, slack is defined as the worst slack of all paths either launched by a transition at the sink pin (if the -launch option is used) or captured by a transition at the sink pin (if the -capture option is used).
Note that the use of this filter might greatly increase the runtime of this report. However, when used with the -capture option the effect on runtime should be small, since PrimeTime can make use of cached slack values to avoid expensive recomputations. You cannot use this option in summary reports.
Note that the use of this filter might greatly increase the runtime of this report. However, when used with the -capture option the effect on runtime should be small, since PrimeTime can make use of cached slack values to avoid expensive recomputations. You cannot use this option in summary reports.
-include_uncertainty_in_skew
Specifies that the user-defined uncertainty between the sequential devices in a launch/capture pair is to be considered a component of skew. You cannot use this option in summary or skew reports.
-verbose
Generates a more detailed report; instead of a single line per pin, verbose reports trace the entire source-to-sink path through a clock network to show how the final reported attribute (skew, latency or transition time) was accumulated over the course of the path. You cannot use this option in summary reports.
-significant_digits digits
Specifies the number of digits after the decimal point to be displayed for time values in the generated report. Allowed values are 0-13; the default is determined by the report_default_significant_digits variable, which has a default of 2. Use this option if you want to override the default. This option controls only the number of digits displayed, not the precision used internally for analysis. For analysis, PrimeTime uses the full precision of the platform's fixed-precision, floating-point arithmetic capability.
-show_clocks
Shows the launching and capturing clocks for every interclock skew entry in the report. This is useful if from_clock_list or to_clock_list contain more than one clock each. You cannot use this option in interclock skew reports.
-crosstalk_delta
Shows the delta delay and delta transition time in verbose reports. The deltas are computed during crosstalk signal integrity analysis, or they can be annotated manually using the set_annotated_delay -delta_only and set_annotated_transition -delta_only commands. Note that the -crosstalk_delta option reports only the calculated or annotated deltas, it does not initiate crosstalk analysis. Only deltas on input pins are shown.
-derate
Shows the derating factors in the report. By default, derating factors are not displayed. Derating factors are only shown when you specify the -verbose option.
-variation
Shows variation information. Using this option is allowed only when detailed variation-aware clock analysis is enabled. Without -variation, only the quantile or mean value is displayed, as specified using the variation_derived_scalar_attribute_mode variable. With -variation, the quantile, mean and either the standard deviation (for skew reports) or sensitivity (for latency or transition reports) is displayed for both verbose and non-verbose reports. In verbose reports, additional statistical info regarding individual path increments appear in new columns, namely the sensitivity, mean and increment, where the increment refers either to the quantile or the effective delay depending on the variation_report_timing_increment_format variable.
-sort_by sort_attr
Sorts the entries in the report with respect to the specified variational attribute. This option can be used only with the -summary option and only when detailed variation-aware clock analysis is enabled. Note that this option only controls the ranking of entries and not their display. You can specify the following values for sort_attr:
- quantile - Ranks entries using their quantile values.
- mean - Ranks entries using their mean values.
- sensitivity - Ranks entries using their sensitivity values. This option cannot be used in a skew or interclock_skew report.
-clock_crossing
Indicates that only skews between interacting clock domains (i.e. clocks connected by at least one non-false data path) is included in the report. This option can only be used in interclock_skew reports.
-include_clock_gating
Include clock pins of clock-gating checks in the report. By default, only sequential devices that exercise a setup/hold check are reported by report_clock_timing. This option additionally allows clock-gating checks to be reported.
-nosplit
Prevents line-splitting and facilitates writing software to extract information from the report output. If this option is not used, most of the design information is listed in fixed-width columns. If the information in a given field exceeds the column width, the next field begins on a new line, starting in the correct column.
-pre_commands pre_command_string
This option is available only if you invoke PrimeTime with the -multi_scenario option. This option allows you to specify a string of commands to be executed in the slave context before the execution of the merged reporting command. Commands must be grouped using the ";" character. The maximum size of a command is 1000 chars.
-post_commands post_command_string
This option is available only if you invoke PrimeTime with the -multi_scenario option. This option allows you to specify a string of commands to be executed in the slave context after the execution of the merged reporting commands. Commands are grouped using the ";" character. The maximum size of a command is 1000 chars.
DESCRIPTION
This command generates a report of clock timing information for the current design.
There are several reporting types provided, which allow you to examine skew, latency and transition time attributes of a given clock network or subnetwork at various levels of generality. By default, the report displays the values of these attributes only at sink pins (that is, the clock pins of sequential devices) of the clock network. You use the -verboseoption to display source-to-sink path traces. If you specify several clock domains, the report_clock_timing command generates a separate subreport for each clock domain.
At the highest level of abstraction is the summary style report, which provides only a list of maxima and minima of the skew, latency, and transition time attributes over the given networks. At a lower level of abstraction are the transition, latency, and skew type reports, called list style reports, in which you can sort, filter and display the worst set of sink pins in the given network with respect to a single attribute of interest. For skew reports, each report entry is a pair of sink pins and their relative skew. For transition time or latency reports, each entry corresponds to a single sink pin. The lowest level of abstraction is provided by verbose mode, which replaces every sink pin in a list style report by a corresponding source-to-sink path trace.
In both summary and list style reports, the rightmost column is an attributed column. Corresponding to each sink pin, the set of character symbols in this column indicates the following:
Skews reported by report_clock_timing are local skews only. Local skew exists from one sink pin to another only if their associated sequential devices are connected via a data path in the appropriate from-to sense. Note that even if all data paths between the sequential devices are false because of user-defined exceptions, the skew still qualifies as local skew if the devices are connected topologically.
If detailed variation-aware clock analysis is enabled using the variation_analysis_mode variable, the report_clock_timing command evaluates the attributes of latency, transition time and skew as statistical entities. By default, the quantile of these attributes is used for both ranking and display purposes. The ranking can be controlled using the -sort_by option, while the display parameter can be changed from quantile to mean using the variation_derived_scalar_attribute_mode variable. To augment the display with additional statistical parameters of report_clock_timing attributes, see the -variation option.
There are several reporting types provided, which allow you to examine skew, latency and transition time attributes of a given clock network or subnetwork at various levels of generality. By default, the report displays the values of these attributes only at sink pins (that is, the clock pins of sequential devices) of the clock network. You use the -verboseoption to display source-to-sink path traces. If you specify several clock domains, the report_clock_timing command generates a separate subreport for each clock domain.
At the highest level of abstraction is the summary style report, which provides only a list of maxima and minima of the skew, latency, and transition time attributes over the given networks. At a lower level of abstraction are the transition, latency, and skew type reports, called list style reports, in which you can sort, filter and display the worst set of sink pins in the given network with respect to a single attribute of interest. For skew reports, each report entry is a pair of sink pins and their relative skew. For transition time or latency reports, each entry corresponds to a single sink pin. The lowest level of abstraction is provided by verbose mode, which replaces every sink pin in a list style report by a corresponding source-to-sink path trace.
In both summary and list style reports, the rightmost column is an attributed column. Corresponding to each sink pin, the set of character symbols in this column indicates the following:
Symbol Meaning ------ ------- r Rising transition f Falling transition p Propagated clock to this pin i Clock inversion to this pin - Launching transition + Capturing transition m Library clock insertion delayIn verbose mode, back-annotations on path elements in the timing path are indicated using a character symbol. For definitions of these character symbols, see the manual page of the report_timing command.
Skews reported by report_clock_timing are local skews only. Local skew exists from one sink pin to another only if their associated sequential devices are connected via a data path in the appropriate from-to sense. Note that even if all data paths between the sequential devices are false because of user-defined exceptions, the skew still qualifies as local skew if the devices are connected topologically.
If detailed variation-aware clock analysis is enabled using the variation_analysis_mode variable, the report_clock_timing command evaluates the attributes of latency, transition time and skew as statistical entities. By default, the quantile of these attributes is used for both ranking and display purposes. The ranking can be controlled using the -sort_by option, while the display parameter can be changed from quantile to mean using the variation_derived_scalar_attribute_mode variable. To augment the display with additional statistical parameters of report_clock_timing attributes, see the -variation option.
No comments:
Post a Comment