timing loop warning when synthesis

[hhhsiang]

Is there an existing CVA6 bug for this?

• I have searched the existing bug issues

Bug Description

When I synthesize cva6 with WB cache, there is timing loop warning occurred in cache system. It happened in tag_cmp and miss_hander. I think it is a significant warning. Is it normal or acceptable?

It seems to relate to #1761, but the problem is still exist.

The following is the timing loop path：

Startpoint: gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u7/O (internal pin)
Endpoint: gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u7/O (internal pin)
Path Group: (none)
Path Type: max

---

gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u7/O (INV6CK)
0.00 0.00 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n1954 (net)
3 0.00 0.00 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u6/I (BUF1S)
0.00 0.00 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u6/O (BUF1S)
0.17 0.17 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n4119 (net)
1 0.00 0.17 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u4/I (INV1S)
0.00 0.17 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u4/O (INV1S)
0.16 0.33 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n1935 (net)
1 0.00 0.33 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u5/I (INV3)
0.00 0.33 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u5/O (INV3)
1.35 1.69 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/gnt_o[3] (net)
211 0.00 1.69 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u682/B1 (AOI22S)
0.00 1.69 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u682/O (AOI22S)
0.13 1.82 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n660 (net)
1 0.00 1.82 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u1502/I1 (ND3)
0.00 1.82 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u1502/O (ND3)
0.33 2.15 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/req_o[2] (net)
4 0.00 2.15 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/req_o[2] (tag_cmp_00000005_0000000c_010242)
0.00 2.15 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/req_ram[2] (net)
0.00 2.15 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/u15/I1 (NR3)
0.00 2.15 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/u15/O (NR3)
0.29 2.44 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/n302 (net)
1 0.00 2.44 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/u18/I1 (ND3)
0.00 2.44 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/u18/O (ND3)
0.24 2.68 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/n_69_net_ (net)
2 0.00 2.68 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/req_i (dcache_valid_array_real_sram_00000040_1_00000100)
0.00 2.68 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/req_i (net)
0.00 2.68 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/u15/I (INV1S)
0.00 2.68 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/u15/O (INV1S)
0.18 2.85 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/n70 (net)
1 0.00 2.85 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/u11/I1 (NR2P)
0.00 2.85 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/u11/O (NR2P)
0.23 3.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/oe (net)
1 0.00 3.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/gen_cut_0__dcache_valid_array_wrapper/oe (dcache_valid_array_wrapper)
0.00 3.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/gen_cut_0__dcache_valid_array_wrapper/oe (net)
0.00 3.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/gen_cut_0__dcache_valid_array_wrapper/i_dcache_valid_array/OE (SUMA180_256X8X8BM1)
0.00 3.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/gen_cut_0__dcache_valid_array_wrapper/i_dcache_valid_array/DO49 (SUMA180_256X8X8BM1)
0.78 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/gen_cut_0__dcache_valid_array_wrapper/do[49] (net)
2 0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/gen_cut_0__dcache_valid_array_wrapper/do[49] (dcache_valid_array_wrapper)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/rdata_o[49] (net)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/valid_dirty_sram/rdata_o[49] (dcache_valid_array_real_sram_00000040_1_00000100)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/rdata_ram[1045] (net)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/rdata_i[1045] (tag_cmp_00000005_0000000c_010242)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/rdata_i[1045] (net)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u29/I (BUF2)
0.00 3.86 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u29/O (BUF2)
0.23 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/rdata_o[1045] (net)
4 0.00 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/rdata_o[1045] (tag_cmp_00000005_0000000c_010242)
0.00 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/rdata[1045] (net)
0.00 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/data_i[1045] (miss_handler_00000004_244242)
0.00 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/data_i[1045] (net)
0.00 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u27/I1 (ND2S)
0.00 4.09 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u27/O (ND2S)
0.18 4.27 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/n4091 (net)
2 0.00 4.27 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u52/I1 (ND2S)
0.00 4.27 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u52/O (ND2S)
0.17 4.44 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/n3973 (net)
1 0.00 4.44 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u169/I1 (OR2P)
0.00 4.44 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u169/O (OR2P)
0.28 4.73 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/n4546 (net)
3 0.00 4.73 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u6/I2 (NR2F)
0.00 4.73 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u6/O (NR2F)
0.09 4.82 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/n4409 (net)
4 0.00 4.82 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u5/I2 (OR2T)
0.00 4.82 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u5/O (OR2T)
0.35 5.16 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/n5957 (net)
20 0.00 5.16 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u76/I2 (OR2)
0.00 5.16 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u76/O (OR2)
0.30 5.47 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/be_o[0] (net)
2 0.00 5.47 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u64/I (INV2)
0.00 5.47 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u64/O (INV2)
0.10 5.56 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/n4519 (net)
1 0.00 5.56 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u119/I1 (ND3P)
0.00 5.56 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/u119/O (ND3P)
0.14 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/req_o[0] (net)
2 0.00 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_miss_handler/req_o[0] (miss_handler_00000004_244242)
0.00 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/req[0] (net)
0.00 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/req_i[0] (tag_cmp_00000005_0000000c_010242)
0.00 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/req_i[0] (net)
0.00 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u65/I2 (NR2T)
0.00 5.70 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u65/O (NR2T)
0.35 6.05 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n4125 (net)
10 0.00 6.05 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u1494/I1 (AN2T)
0.00 6.05 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u1494/O (AN2T)
0.57 6.63 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/gnt_o[2] (net)
20 0.00 6.63 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u9/I1 (ND3P)
0.00 6.63 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u9/O (ND3P)
0.56 7.18 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n1953 (net)
20 0.00 7.18 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u7/I (INV6CK)
0.00 7.18 f
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/u7/O (INV6CK)
0.15 7.33 r
gen_cache_wb_i_cache_subsystem/i_nbdcache/i_tag_cmp/n1954 (net)
3 0.00 7.33 r
data arrival time 7.33