Please advice about skew report

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yaseong

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I am beginner with Astro. I finished cts step but skew higher than 13ns. I can't find what is problem:sad: Please advice what I check .
And does anybody explain about meaning of (NONSTOP SINK) in the skew report?

======== Clock Global Skew Report ======================================

Clock: ipclk
Pin: M_CLOCKGEN/U14/O
Net: ipclk

Phase Type = rise && fall
Operating Condition = worst
The clock global skew = 13.491
The longest path delay = 15.801
The shortest path delay = 2.310

The longest path delay end pin: M_CORE_TOP/M_TG_TOP/M_VRAMPCAL/vcal_count_reg_1_/CK
The shortest path delay end pin: M_CORE_TOP/M_REGBANK/ff_323_reg_3_/CK



The Longest Path:
====================================================================
Pin Cap Fanout Trans Incr Arri Master/Net
--------------------------------------------------------------------
M_CLOCKGEN/U14/O 0.076 2 0.251 0.000 r ipclk
INV8CKG10B12I1/I 0.251 0.001 0.001 r INV12CK
INV8CKG10B12I1/O 0.150 1 0.144 0.112 0.112 f ipclk_G10B12I1
INV1CKG10B11I1/I 0.156 0.015 0.127 f INV12
INV1CKG10B11I1/O 0.196 4 0.188 0.127 0.255 r ipclk_G10B11I1ASTHIRNet6797
INV1CKG10B10I1/I 0.189 0.000 0.255 r INV2CK
INV1CKG10B10I1/O 0.069 1 0.288 0.197 0.452 f ipclk_G10B10I1
INV1CKG10B9I1/I 0.290 0.003 0.455 f INV1CK
INV1CKG10B9I1/O 0.073 1 0.674 0.392 0.848 r ipclk_G10B9I1
BUF12CKG10B8I1/I 0.677 0.004 0.851 r BUF12CK
BUF12CKG10B8I1/O 0.296 2 0.228 0.312 1.164 r ipclk_G10B8I1ASTHIRNet4638
INV12CKG10B7I2/I 0.240 0.016 1.179 r INV12CK
INV12CKG10B7I2/O 0.562 2 0.360 0.242 1.421 f ipclk_G10B7I2ASTHIRNet6477
INV12CKG10B6I2/I 0.411 0.064 1.485 f INV12CK
INV12CKG10B6I2/O 0.516 1 0.385 0.264 1.750 r ipclk_G10B6I2
INV12CKG10B5I3/I 0.524 0.174 1.924 r INV12CK
INV12CKG10B5I3/O 0.579 3 0.424 0.306 2.230 f ipclk_G10B5I3ASTHIRNet5239
INV12CKG10B4I5/I 0.428 0.006 2.235 f INV8
INV12CKG10B4I5/O 0.294 3 0.396 0.277 2.513 r ipclk_G10B4I5ASTHIRNet7200
M_SCANWRAPPER/U45/A1
0.401 0.007 2.519 r AO22T
M_SCANWRAPPER/U45/O
0.060 3 0.225 0.359 2.878 r sclASTHIRNet5595
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/INV1CKG11IPI1_1/I
0.225 0.000 2.878 r INV1CK
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/INV1CKG11IPI1_1/O
0.085 1 0.735 0.445 3.323 f M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/scl_G11IPI1ASTHNet5806
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/INV8CKG11B1I1_1/I
0.739 0.004 3.328 f INV8CK
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/INV8CKG11B1I1_1/O
0.059 4 0.196 0.147 3.475 r M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/scl_G11IPI1_G11B1I1ASTHNet6231
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/write_reg/CK( NONSTOP SINK )
0.197 0.001 3.476 r QDFZRBP
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/write_reg/Q
0.806 3 1.402 1.246 4.722 f M_CORE_TOP/n11
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/U108/I1
1.404 0.002 4.725 f ND2
M_CORE_TOP/M_IIC_TOP/M_IIC_SLAVE/U108/O
0.035 2 0.610 0.493 5.217 r M_CORE_TOP/M_IIC_TOP/web_slave
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U96/A1
0.610 0.000 5.217 r AOI12S
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U96/O
0.006 1 0.213 0.139 5.356 f M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/n34
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U114/B2
0.213 0.000 5.356 f AN3B2S
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U114/O
0.012 2 0.442 0.299 5.655 r M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/n2
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U134/A
0.442 0.000 5.655 r MUX2F
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U134/O
0.075 2 0.256 0.475 6.130 r M_CORE_TOP/wstrobeASTHIRNet6662
M_CORE_TOP/M_REGBANK/INV1CKG14IPI1/I
0.256 0.000 6.131 r INV1CK
M_CORE_TOP/M_REGBANK/INV1CKG14IPI1/O
0.045 1 0.432 0.288 6.419 f M_CORE_TOP/M_REGBANK/wstrobe_G14IPI1ASTHNet7484
M_CORE_TOP/M_REGBANK/INV8CKG14B1I1/I
0.432 0.001 6.419 f INV8CK
M_CORE_TOP/M_REGBANK/INV8CKG14B1I1/O
0.424 1 0.457 0.306 6.726 r M_CORE_TOP/M_REGBANK/wstrobe_G14IPI1_G14B1I1ASTHNet6295
M_CORE_TOP/M_REGBANK/INV8CKG14B2I1/I
0.569 0.141 6.867 r INV8CK
M_CORE_TOP/M_REGBANK/INV8CKG14B2I1/O
0.396 2 0.443 0.319 7.185 f M_CORE_TOP/M_REGBANK/wstrobe_G14IPI1_G14B2I1ASTHNet5848
M_CORE_TOP/M_REGBANK/INV8CKG14B3I2/I
0.465 0.027 7.212 f INV8CK
M_CORE_TOP/M_REGBANK/INV8CKG14B3I2/O
0.071 5 0.169 0.131 7.342 r M_CORE_TOP/M_REGBANK/wstrobe_G14IPI1_G14B3I2ASTHNet4831
M_CORE_TOP/M_REGBANK/ff_24_reg_1_/CK( NONSTOP SINK )
0.170 0.001 7.343 r QDFZRBP
M_CORE_TOP/M_REGBANK/ff_24_reg_1_/Q
0.140 10 0.527 0.684 8.027 r rg_clkdiv[1]
M_CLOCKGEN/U30/I1
0.529 0.003 8.030 r NR2
M_CLOCKGEN/U30/O 0.009 1 0.190 0.146 8.176 f M_CLOCKGEN/n3
M_CLOCKGEN/U33/S 0.190 0.000 8.176 f MUX2
M_CLOCKGEN/U33/O 0.008 1 0.138 0.335 8.512 r M_CLOCKGEN/clkmux
M_CLOCKGEN/U34/A 0.138 0.000 8.512 r MUX2T
M_CLOCKGEN/U34/O 0.119 4 0.376 0.462 8.974 r M_CLOCKGEN/dbipclk_int
M_CLOCKGEN/INV8CKG8B2I1/I
0.379 0.004 8.978 r INV8CK
M_CLOCKGEN/INV8CKG8B2I1/O
0.032 1 0.104 0.079 9.057 f M_CLOCKGEN/dbipclk_int_G8B2I1ASTHNet5582
M_CLOCKGEN/INV1CKG8B1I1/I
0.104 0.001 9.058 f INV1CK
M_CLOCKGEN/INV1CKG8B1I1/O
0.005 1 0.096 0.069 9.127 r M_CLOCKGEN/dbipclk_int_G8B1I1ASTHNet5029
M_CLOCKGEN/ipclk_int_reg/CK( NONSTOP SINK )
0.096 0.000 9.127 r JKZRBN
M_CLOCKGEN/ipclk_int_reg/Q
0.034 3 0.360 0.913 10.040 r n421ASTHIRNet5056
M_CLOCKGEN/DELBG9B13I1/I
0.360 0.000 10.040 r BUF1S
M_CLOCKGEN/DELBG9B13I1/O
0.007 1 0.198 0.220 10.260 r M_CLOCKGEN/n421_G9B13I1ASTHNet4472
M_CLOCKGEN/DELBG9B12I1/I
0.198 0.000 10.261 r DELB
M_CLOCKGEN/DELBG9B12I1/O
0.003 1 0.105 0.560 10.821 r M_CLOCKGEN/n421_G9B12I1ASTHNet7087
M_CLOCKGEN/DELBG9B11I1/I
0.105 0.000 10.821 r BUF1S
M_CLOCKGEN/DELBG9B11I1/O
0.004 1 0.138 0.157 10.978 r M_CLOCKGEN/n421_G9B11I1ASTHNet5780
M_CLOCKGEN/DELBG9B10I1/I
0.138 0.000 10.978 r BUF1
M_CLOCKGEN/DELBG9B10I1/O
0.004 1 0.086 0.153 11.131 r M_CLOCKGEN/n421_G9B10I1ASTHNet5291
M_CLOCKGEN/DELBG9B9I1/I
0.086 0.000 11.132 r DELB
M_CLOCKGEN/DELBG9B9I1/O
0.003 1 0.105 0.543 11.675 r M_CLOCKGEN/n421_G9B9I1ASTHNet4740
M_CLOCKGEN/DELBG9B8I1/I
0.105 0.000 11.675 r BUF1S
M_CLOCKGEN/DELBG9B8I1/O
0.004 1 0.139 0.157 11.832 r M_CLOCKGEN/n421_G9B8I1ASTHNet7351
M_CLOCKGEN/DELBG9B7I1/I
0.139 0.000 11.832 r BUF1
M_CLOCKGEN/DELBG9B7I1/O
0.004 1 0.085 0.153 11.985 r M_CLOCKGEN/n421_G9B7I1ASTHNet6732
M_CLOCKGEN/DELBG9B6I1/I
0.085 0.000 11.986 r BUF1S
M_CLOCKGEN/DELBG9B6I1/O
0.007 1 0.186 0.178 12.163 r M_CLOCKGEN/n421_G9B6I1ASTHNet6212
M_CLOCKGEN/INV1CKG9B5I1/I
0.186 0.000 12.163 r INV1CK
M_CLOCKGEN/INV1CKG9B5I1/O
0.005 1 0.105 0.087 12.250 f M_CLOCKGEN/n421_G9B5I1ASTHNet5704
M_CLOCKGEN/INV1CKG9B4I1/I
0.105 0.000 12.250 f INV1CK
M_CLOCKGEN/INV1CKG9B4I1/O
0.005 1 0.098 0.069 12.320 r M_CLOCKGEN/n421_G9B4I1ASTHNet5236
M_CLOCKGEN/INV1CKG9B3I1/I
0.098 0.000 12.320 r INV1CK
M_CLOCKGEN/INV1CKG9B3I1/O
0.005 1 0.089 0.074 12.393 f M_CLOCKGEN/n421_G9B3I1ASTHNet7034
M_CLOCKGEN/INV1CKG9B2I1/I
0.089 0.000 12.393 f INV1CK
M_CLOCKGEN/INV1CKG9B2I1/O
0.007 1 0.104 0.071 12.464 r M_CLOCKGEN/n421_G9B2I1ASTHNet6464
M_CLOCKGEN/BUF2CKG9B1I1/I
0.104 0.000 12.464 r BUF2CK
M_CLOCKGEN/BUF2CKG9B1I1/O
0.010 1 0.088 0.166 12.630 r M_CLOCKGEN/n421_G9B1I1ASTHNet5985
M_CLOCKGEN/U38/B 0.089 0.000 12.630 r MUX3S
M_CLOCKGEN/U38/O 0.129 1 2.361 1.453 14.084 r M_CLOCKGEN/N30
M_CLOCKGEN/U7/B1 2.371 0.014 14.097 r MOAI1
M_CLOCKGEN/U7/O 0.146 1 2.244 0.940 15.037 r adcclk
M_CORE_TOP/M_TG_TOP/INV8CKG17B2I1/I
2.257 0.016 15.053 r INV8CK
M_CORE_TOP/M_TG_TOP/INV8CKG17B2I1/O
0.354 3 0.690 0.461 15.515 f M_CORE_TOP/M_TG_TOP/adcclk_G17B2I1ASTHIRNet7105
M_CORE_TOP/M_TG_TOP/INV8CKG17B1I3/I
0.703 0.016 15.531 f INV8CK
M_CORE_TOP/M_TG_TOP/INV8CKG17B1I3/O
0.213 25 0.333 0.256 15.786 r M_CORE_TOP/M_TG_TOP/adcclk_G17B1I3ASTHIRNet5459
M_CORE_TOP/M_TG_TOP/M_VRAMPCAL/vcal_count_reg_1_/CK( SINK )
0.345 0.015 15.801 r QDFZRBN
[clock delay] 15.801
====================================================================
The Shortest Path:
====================================================================
Pin Cap Fanout Trans Incr Arri Master/Net
--------------------------------------------------------------------
M_CLOCKGEN/U14/O 0.076 2 0.247 0.000 r ipclk
INV8CKG10B12I1/I 0.247 0.001 0.001 r INV12CK
INV8CKG10B12I1/O 0.150 1 0.144 0.111 0.112 f ipclk_G10B12I1
INV1CKG10B11I1/I 0.156 0.015 0.127 f INV12
INV1CKG10B11I1/O 0.196 4 0.188 0.127 0.254 r ipclk_G10B11I1ASTHIRNet6797
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U134/B
0.207 0.023 0.277 r MUX2F
M_CORE_TOP/M_IIC_TOP/M_IIC_INTERFACE/U134/O
0.075 2 0.253 0.437 0.714 r M_CORE_TOP/wstrobeASTHIRNet6662
M_CORE_TOP/M_REGBANK/INV12CKG14B7I1/I
0.253 0.001 0.715 r INV12CK
M_CORE_TOP/M_REGBANK/INV12CKG14B7I1/O
0.492 1 0.326 0.224 0.939 f M_CORE_TOP/M_REGBANK/wstrobe_G14B7I1ASTHNet4426
M_CORE_TOP/M_REGBANK/INV12CKG14B6I1/I
0.478 0.190 1.129 f INV12CK
M_CORE_TOP/M_REGBANK/INV12CKG14B6I1/O
0.135 2 0.187 0.143 1.272 r M_CORE_TOP/M_REGBANK/wstrobe_G14B6I1ASTHNet7033
M_CORE_TOP/M_REGBANK/INV12CKG14B5I1/I
0.190 0.004 1.276 r INV12
M_CORE_TOP/M_REGBANK/INV12CKG14B5I1/O
0.261 1 0.141 0.104 1.380 f M_CORE_TOP/M_REGBANK/wstrobe_G14B5I1ASTHNet5700
M_CORE_TOP/M_REGBANK/INV12CKG14B4I2/I
0.179 0.048 1.428 f INV12CK
M_CORE_TOP/M_REGBANK/INV12CKG14B4I2/O
0.370 4 0.263 0.167 1.595 r M_CORE_TOP/M_REGBANK/wstrobe_G14B4I2ASTHNet7204
M_CORE_TOP/M_REGBANK/BUF12CKG14B3I8/I
0.282 0.024 1.619 r BUF12CK
M_CORE_TOP/M_REGBANK/BUF12CKG14B3I8/O
0.207 3 0.171 0.233 1.852 r M_CORE_TOP/M_REGBANK/wstrobe_G14B3I8ASTHNet4763
M_CORE_TOP/M_REGBANK/BUF12CKG14B2I13/I
0.177 0.007 1.859 r BUF12CK
M_CORE_TOP/M_REGBANK/BUF12CKG14B2I13/O
0.207 5 0.169 0.216 2.075 r M_CORE_TOP/M_REGBANK/wstrobe_G14B2I13ASTHNet7045
M_CORE_TOP/M_REGBANK/BUF6CKG14B1I71/I
0.173 0.006 2.081 r BUF12CK
M_CORE_TOP/M_REGBANK/BUF6CKG14B1I71/O
0.253 33 0.193 0.229 2.310 r M_CORE_TOP/M_REGBANK/wstrobe_G14B1I71ASTHNet7206
M_CORE_TOP/M_REGBANK/ff_323_reg_3_/CK( SINK )
0.194 0.000 2.310 r QDFZRBN
[clock delay] 2.310
====================================================================
 

normally CTS engine stops at sink pin. A non-stop sink pin is a sink pin that CTS will trace through during clcok tree synthesis. In your case, the non-stop pin seems to be a generated clock pin.

most likely your bad skew is also due to the generated clock.
 
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