Since the related PR was landed before the CI benchmark machine was restarted, these regressions were not caught before it was merged.
I'm not sure if there are other built-in modules affected, but the URL module is one such user of toUSVString().
https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1306/consoleFull
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='altspaces' *** -17.43 % ±1.75% ±2.33% ±3.03%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='encodefake' *** -25.28 % ±2.79% ±3.72% ±4.86%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='encodelast' *** -20.54 % ±2.20% ±2.93% ±3.82%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='encodemany' *** -16.30 % ±2.05% ±2.74% ±3.57%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='manyblankpairs' *** -38.49 % ±4.55% ±6.11% ±8.09%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='manypairs' *** -16.03 % ±2.22% ±2.96% ±3.86%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='multicharsep' *** -27.57 % ±2.15% ±2.87% ±3.76%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='multivalue' *** -23.27 % ±1.78% ±2.37% ±3.08%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='multivaluemany' *** -16.69 % ±1.17% ±1.56% ±2.05%
url/legacy-vs-whatwg-url-searchparams-parse.js n=1000000 method='whatwg' searchParam='noencode' *** -26.78 % ±2.35% ±3.13% ±4.09%
url/url-searchparams-creation.js n=1000000 inputType='iterable' type='array' *** -25.56 % ±0.71% ±0.95% ±1.24%
url/url-searchparams-creation.js n=1000000 inputType='iterable' type='encodelast' *** -40.80 % ±1.59% ±2.14% ±2.81%
url/url-searchparams-creation.js n=1000000 inputType='iterable' type='encodemany' *** -41.81 % ±2.19% ±2.91% ±3.79%
url/url-searchparams-creation.js n=1000000 inputType='iterable' type='multiprimitives' *** -42.60 % ±1.83% ±2.46% ±3.23%
url/url-searchparams-creation.js n=1000000 inputType='iterable' type='noencode' *** -39.99 % ±1.57% ±2.11% ±2.77%
url/url-searchparams-creation.js n=1000000 inputType='object' type='array' *** -29.03 % ±1.94% ±2.58% ±3.36%
url/url-searchparams-creation.js n=1000000 inputType='object' type='encodelast' *** -34.75 % ±1.69% ±2.27% ±2.99%
url/url-searchparams-creation.js n=1000000 inputType='object' type='encodemany' *** -35.23 % ±1.30% ±1.74% ±2.28%
url/url-searchparams-creation.js n=1000000 inputType='object' type='multiprimitives' *** -35.42 % ±2.37% ±3.17% ±4.17%
url/url-searchparams-creation.js n=1000000 inputType='object' type='noencode' *** -35.35 % ±1.82% ±2.43% ±3.19%
url/url-searchparams-creation.js n=1000000 inputType='string' type='array' *** -23.30 % ±2.24% ±2.98% ±3.88%
url/url-searchparams-creation.js n=1000000 inputType='string' type='encodelast' *** -26.13 % ±2.25% ±3.02% ±3.98%
url/url-searchparams-creation.js n=1000000 inputType='string' type='encodemany' *** -23.93 % ±1.70% ±2.27% ±2.95%
url/url-searchparams-creation.js n=1000000 inputType='string' type='multiprimitives' *** -24.05 % ±1.58% ±2.10% ±2.74%
url/url-searchparams-creation.js n=1000000 inputType='string' type='noencode' *** -23.97 % ±1.77% ±2.35% ±3.06%
url/url-searchparams-read.js n=20000000 param='nonexistent' accessMethod='get' *** -60.10 % ±1.35% ±1.80% ±2.34%
url/url-searchparams-read.js n=20000000 param='nonexistent' accessMethod='getAll' *** -57.29 % ±2.38% ±3.20% ±4.22%
url/url-searchparams-read.js n=20000000 param='nonexistent' accessMethod='has' *** -58.05 % ±2.19% ±2.94% ±3.87%
url/url-searchparams-read.js n=20000000 param='one' accessMethod='get' *** -60.58 % ±1.58% ±2.11% ±2.75%
url/url-searchparams-read.js n=20000000 param='one' accessMethod='getAll' *** -39.72 % ±2.91% ±3.87% ±5.04%
url/url-searchparams-read.js n=20000000 param='one' accessMethod='has' *** -60.04 % ±2.66% ±3.57% ±4.71%
url/url-searchparams-read.js n=20000000 param='three' accessMethod='get' *** -57.71 % ±1.36% ±1.81% ±2.36%
url/url-searchparams-read.js n=20000000 param='three' accessMethod='getAll' *** -37.37 % ±2.63% ±3.51% ±4.60%
url/url-searchparams-read.js n=20000000 param='three' accessMethod='has' *** -58.09 % ±2.38% ±3.19% ±4.20%
url/url-searchparams-read.js n=20000000 param='two' accessMethod='get' *** -58.71 % ±1.70% ±2.27% ±2.95%
url/url-searchparams-read.js n=20000000 param='two' accessMethod='getAll' *** -37.93 % ±2.61% ±3.47% ±4.52%
url/url-searchparams-read.js n=20000000 param='two' accessMethod='has' *** -57.99 % ±2.55% ±3.40% ±4.44%
url/usvstring.js n=50000000 input='nonstring' *** -45.54 % ±3.05% ±4.08% ±5.35%
url/usvstring.js n=50000000 input='valid' *** -73.28 % ±2.34% ±3.14% ±4.15%
url/usvstring.js n=50000000 input='validsurr' *** -14.33 % ±2.56% ±3.42% ±4.48%
/cc @anonrig
Since the related PR was landed before the CI benchmark machine was restarted, these regressions were not caught before it was merged.
I'm not sure if there are other built-in modules affected, but the URL module is one such user of
toUSVString().https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1306/consoleFull
/cc @anonrig