Skip heap profile sampling unless profiling by jakebailey · Pull Request #65338 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-11-05T17:45:55Z

This will probably be barely anything, but, might as well try.

Go samples allocations for the heap profile by default, walking the stack every 512 KiB or so allocated, even though the command line only writes a memory profile when --pprofDir is passed. Turn sampling off for command line runs and turn it back on when profiling begins. The language server and API can take heap profiles on demand at any time, so they keep sampling.

Jake Bailey (jakebailey) · 2026-11-05T17:46:09Z

TypeScript Bot (@typescript-bot) perf test this faster

typescript-automation · 2026-11-05T17:46:15Z

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
`perf test this faster`	✅ Started	👀 Results

Copilot

🟢 Approval recommended

No active review issues remain for the CLI heap-sampling changes.

No open issues 🎉

What changed in this PR

This PR reduces heap-profile sampling overhead during normal compiler CLI execution while preserving profiling support.

Changes:

Disable heap sampling for CLI execution, leaving language server and API modes unchanged.
Save the original sampling rate and restore it when profiling begins.

File	Description
`tsc/internal/pprof/pprof.go`	Adds a helper to disable heap sampling and restores the original rate in `BeginProfiling`.
`tsc/cmd/tsc/main.go`	Disables sampling after dispatching language server and API modes.

_{Review effort: Balanced}

typescript-automation · 2026-11-05T18:47:17Z

Jake Bailey (@jakebailey)
The results of the perf run you requested are in!

Here they are:

tsc

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-Unions - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_88,466	_88,466	_~	_~	_~	_{p=1.000 n=20}
_Types	_79,607	_79,607	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{106,421k (± 0.03%)}	_{106,417k (± 0.03%)}	_~	_106,329k	_106,534k	_{p=0.644 n=20}
_{Memory Allocs}	_{1,261,900 (± 0.01%)}	_{1,261,964 (± 0.01%)}	_~	_1,261,536	_1,262,412	_{p=0.402 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.022s (± 3.47%)}	_{0.022s (± 3.04%)}	_~	_0.020s	_0.025s	_{p=0.287 n=20}
_{Bind Time}	_{0.009s (± 7.01%)}	_{0.009s (± 5.49%)}	_~	_0.007s	_0.011s	_{p=0.967 n=20}
_{Check Time}	_{0.217s (± 1.38%)}	_{0.217s (± 1.60%)}	_~	_0.207s	_0.231s	_{p=0.663 n=20}
_{Emit Time}	_{0.142s (± 1.98%)}	_{0.143s (± 1.58%)}	_~	_0.135s	_0.151s	_{p=0.559 n=20}
_{Total Time}	_{0.394s (± 1.34%)}	_{0.394s (± 1.38%)}	_~	_0.381s	_0.416s	_{p=0.931 n=20}
_{angular-1 - native}
_Errors	₆₃	₆₃	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_756,637	_756,637	_~	_~	_~	_{p=1.000 n=20}
_Types	_549,451	_549,451	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{644,100k (± 0.02%)}	_{644,137k (± 0.02%)}	_~	_643,614k	_644,583k	_{p=0.445 n=20}
_{Memory Allocs}	_{9,551,319 (± 0.13%)}	_{9,539,320 (± 0.04%)}	_~	_9,531,904	_9,565,103	_{p=0.445 n=20}
_{Config Time}	_{0.008s (± 2.73%)}	_{0.008s (± 2.82%)}	_~	_0.008s	_0.009s	_{p=0.748 n=20}
_{Parse Time}	_{0.122s (± 3.06%)}	_{0.117s (± 3.02%)}	_~	_0.105s	_0.132s	_{p=0.092 n=20}
_{Bind Time}	_{0.042s (±10.94%)}	_{0.041s (±12.97%)}	_~	_0.034s	_0.082s	_{p=0.296 n=20}
_{Check Time}	_{0.627s (± 1.62%)}	_{0.631s (± 1.96%)}	_~	_0.589s	_0.682s	_{p=0.857 n=20}
_{Emit Time}	_{0.396s (± 1.13%)}	_{0.395s (± 1.67%)}	_~	_0.381s	_0.443s	_{p=0.297 n=20}
_{Total Time}	_{1.210s (± 1.00%)}	_{1.207s (± 1.70%)}	_~	_1.152s	_1.305s	_{p=0.351 n=20}
_{arktype - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_686,116	_686,116	_~	_~	_~	_{p=1.000 n=20}
_Types	_939,797	_939,797	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{475,967k (± 0.01%)}	_{476,012k (± 0.01%)}	_~	_475,673k	_476,196k	_{p=0.208 n=20}
_{Memory Allocs}	_{12,059,069 (± 0.02%)}	_{12,059,247 (± 0.02%)}	_~	_12,054,763	_12,069,877	_{p=0.925 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.039s (± 3.35%)}	_{0.040s (± 3.66%)}	_~	_0.035s	_0.047s	_{p=0.221 n=20}
_{Bind Time}	_{0.013s (±10.59%)}	_{0.012s (± 9.91%)}	_~	_0.011s	_0.020s	_{p=0.132 n=20}
_{Check Time}	_{0.869s (± 1.17%)}	_{0.844s (± 1.16%)}	_{-0.025s (- 2.83%)}	_0.806s	_0.884s	_{p=0.001 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.950s (± 1.11%)}	_{0.924s (± 1.07%)}	_{-0.025s (- 2.66%)}	_0.883s	_0.967s	_{p=0.001 n=20}
_{class-transformer - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_45,376	_45,376	_~	_~	_~	_{p=1.000 n=20}
_Types	_7,573	_7,573	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{27,756k (± 0.02%)}	_{27,745k (± 0.03%)}	_{-11k (- 0.04%)}	_27,716k	_27,766k	_{p=0.045 n=20}
_{Memory Allocs}	_{248,433 (± 0.06%)}	_{248,525 (± 0.08%)}	_~	_248,005	_249,597	_{p=0.723 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.012s (± 3.33%)}	_{0.011s (± 3.08%)}	_~	_0.009s	_0.012s	_{p=0.511 n=20}
_{Bind Time}	_{0.003s (±11.32%)}	_{0.003s (±10.38%)}	_~	_0.002s	_0.005s	_{p=0.912 n=20}
_{Check Time}	_{0.008s (± 5.35%)}	_{0.008s (± 7.08%)}	_~	_0.006s	_0.009s	_{p=0.594 n=20}
_{Emit Time}	_{0.008s (± 7.47%)}	_{0.007s (± 7.76%)}	_~	_0.006s	_0.010s	_{p=0.598 n=20}
_{Total Time}	_{0.031s (± 1.87%)}	_{0.031s (± 1.81%)}	_~	_0.027s	_0.032s	_{p=0.071 n=20}
_{effect - native}
_Errors	₁₂	₁₂	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_1,235,134	_1,235,134	_~	_~	_~	_{p=1.000 n=20}
_Types	_893,436	_893,436	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{941,647k (± 0.02%)}	_{941,381k (± 0.02%)}	_{-266k (- 0.03%)}	_940,540k	_941,957k	_{p=0.043 n=20}
_{Memory Allocs}	_{12,626,291 (± 0.02%)}	_{12,624,127 (± 0.04%)}	_~	_12,610,318	_12,652,655	_{p=0.068 n=20}
_{Config Time}	_0.002s	_{0.002s (± 7.95%)}	_~	_0.002s	_0.003s	_{p=0.231 n=20}
_{Parse Time}	_{0.151s (± 1.45%)}	_{0.150s (± 3.87%)}	_{-0.001s (- 0.50%)}	_0.140s	_0.191s	_{p=0.048 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.883s (± 1.43%)}	_{0.870s (± 0.76%)}	_~	_0.846s	_0.900s	_{p=0.103 n=20}
_{Emit Time}	_{0.492s (± 1.20%)}	_{0.487s (± 2.13%)}	_~	_0.414s	_0.519s	_{p=0.417 n=20}
_{Total Time}	_{1.623s (± 0.65%)}	_{1.604s (± 0.84%)}	_{-0.019s (- 1.17%)}	_1.531s	_1.655s	_{p=0.024 n=20}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_3,782,394	_3,782,394	_~	_~	_~	_{p=1.000 n=20}
_Types	_1,355,778	_1,355,778	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{1,679,950k (± 0.07%)}	_{1,679,016k (± 0.07%)}	_~	_1,674,375k	_1,682,325k	_{p=0.231 n=20}
_{Memory Allocs}	_{25,743,322 (± 0.13%)}	_{25,740,012 (± 0.15%)}	_~	_25,639,092	_25,988,515	_{p=0.698 n=20}
_{Config Time}	_0.008s	_0.008s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.279s (± 1.89%)}	_{0.275s (± 2.14%)}	_~	_0.246s	_0.308s	_{p=0.084 n=20}
_{Bind Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{2.854s (± 0.58%)}	_{2.830s (± 2.69%)}	_{-0.023s (- 0.82%)}	_2.751s	_3.518s	_{p=0.000 n=20}
_{Emit Time}	_{0.244s (± 2.18%)}	_{0.240s (± 1.34%)}	_~	_0.227s	_0.257s	_{p=0.081 n=20}
_{Total Time}	_{3.866s (± 0.50%)}	_{3.832s (± 2.04%)}	_{-0.034s (- 0.88%)}	_3.716s	_4.532s	_{p=0.000 n=20}
_{sentry - native}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_4,793,266	_4,793,266	_~	_~	_~	_{p=1.000 n=20}
_Types	_2,607,066	_2,607,066	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{2,799,207k (± 0.06%)}	_{2,799,600k (± 0.04%)}	_~	_2,796,669k	_2,804,002k	_{p=0.414 n=20}
_{Memory Allocs}	_{75,034,934 (± 0.33%)}	_{75,102,682 (± 0.42%)}	_~	_74,672,312	_77,630,671	_{p=0.841 n=20}
_{Config Time}	_{0.025s (± 1.13%)}	_{0.024s (± 1.06%)}	_{-0.000s (- 1.42%)}	_0.024s	_0.026s	_{p=0.046 n=20}
_{Parse Time}	_{0.472s (± 5.24%)}	_{0.469s (± 4.75%)}	_~	_0.419s	_0.593s	_{p=0.857 n=20}
_{Bind Time}	_{0.148s (± 9.38%)}	_{0.149s (±10.20%)}	_~	_0.113s	_0.233s	_{p=0.995 n=20}
_{Check Time}	_{6.459s (± 0.60%)}	_{6.382s (± 0.59%)}	_{-0.077s (- 1.19%)}	_6.284s	_6.598s	_{p=0.004 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{7.158s (± 0.78%)}	_{7.081s (± 0.53%)}	_{-0.077s (- 1.07%)}	_6.962s	_7.290s	_{p=0.018 n=20}
_{social-app - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_1,883,060	_1,883,060	_~	_~	_~	_{p=1.000 n=20}
_Types	_1,158,093	_1,158,093	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{952,639k (± 0.02%)}	_{952,828k (± 0.01%)}	_~	_952,200k	_953,338k	_{p=0.064 n=20}
_{Memory Allocs}	_{13,504,885 (± 0.20%)}	_{13,528,168 (± 0.26%)}	_~	_13,445,462	_13,776,135	_{p=0.289 n=20}
_{Config Time}	_{0.007s (± 3.00%)}	_{0.007s (± 2.86%)}	_~	_0.007s	_0.008s	_{p=1.000 n=20}
_{Parse Time}	_{0.156s (± 3.21%)}	_{0.155s (± 3.00%)}	_~	_0.143s	_0.180s	_{p=0.692 n=20}
_{Bind Time}	_{0.041s (± 8.98%)}	_{0.040s (± 8.28%)}	_~	_0.034s	_0.065s	_{p=0.670 n=20}
_{Check Time}	_{1.384s (± 1.27%)}	_{1.360s (± 1.20%)}	_{-0.024s (- 1.73%)}	_1.307s	_1.440s	_{p=0.019 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.608s (± 1.26%)}	_{1.580s (± 1.04%)}	_{-0.028s (- 1.75%)}	_1.535s	_1.660s	_{p=0.030 n=20}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_1,184,972	_1,184,972	_~	_~	_~	_{p=1.000 n=20}
_Types	_438,823	_438,823	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{1,165,599k (± 0.41%)}	_{1,162,346k (± 0.27%)}	_~	_1,148,346k	_1,180,262k	_{p=0.445 n=20}
_{Memory Allocs}	_{47,689,149 (± 0.08%)}	_{47,579,256 (± 0.10%)}	_{-109,893 (- 0.23%)}	_47,378,208	_47,771,734	_{p=0.001 n=20}
_{Config Time}	_{0.001s (±26.29%)}	_{0.002s (±29.41%)}	_~	_0.000s	_0.004s	_{p=0.564 n=20}
_{Parse Time}	_{0.147s (± 1.89%)}	_{0.141s (± 1.30%)}	_{🟩-0.005s (- 3.58%)}	_0.135s	_0.148s	_{p=0.002 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.812s (± 0.87%)}	_{0.796s (± 1.11%)}	_{-0.016s (- 1.99%)}	_0.771s	_0.848s	_{p=0.002 n=20}
_{Emit Time}	_{0.150s (± 3.58%)}	_{0.145s (± 2.27%)}	_~	_0.136s	_0.161s	_{p=0.068 n=20}
_{Total Time}	_{9.628s (± 1.10%)}	_{9.393s (± 0.73%)}	_{-0.235s (- 2.44%)}	_9.114s	_9.660s	_{p=0.000 n=20}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_263,481	_263,481	_~	_~	_~	_{p=1.000 n=20}
_Types	_196,103	_196,103	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{221,527k (± 0.02%)}	_{221,495k (± 0.02%)}	_~	_221,323k	_221,727k	_{p=0.231 n=20}
_{Memory Allocs}	_{2,388,617 (± 0.02%)}	_{2,388,718 (± 0.01%)}	_~	_2,387,098	_2,389,872	_{p=0.602 n=20}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.050s (± 3.90%)}	_{0.049s (± 2.26%)}	_~	_0.044s	_0.053s	_{p=0.549 n=20}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Check Time}	_{0.363s (± 0.65%)}	_{0.361s (± 0.64%)}	_~	_0.354s	_0.371s	_{p=0.198 n=20}
_{Emit Time}	_{0.048s (± 5.02%)}	_{0.046s (± 3.76%)}	_~	_0.042s	_0.052s	_{p=0.199 n=20}
_{Total Time}	_{0.489s (± 0.54%)}	_{0.482s (± 0.55%)}	_{-0.007s (- 1.51%)}	_0.472s	_0.491s	_{p=0.000 n=20}
_{t3code-server - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_4,349,937	_4,349,937	_~	_~	_~	_{p=1.000 n=20}
_Types	_3,042,465	_3,042,465	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{2,394,943k (± 0.03%)}	_{2,394,924k (± 0.02%)}	_~	_2,393,170k	_2,397,242k	_{p=0.583 n=20}
_{Memory Allocs}	_{37,144,283 (± 0.11%)}	_{37,149,958 (± 0.08%)}	_~	_37,079,809	_37,327,414	_{p=0.478 n=20}
_{Config Time}	_0.003s	_0.003s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.251s (± 2.73%)}	_{0.251s (± 2.76%)}	_~	_0.220s	_0.288s	_{p=0.815 n=20}
_{Bind Time}	_{0.101s (±11.94%)}	_{0.087s (± 9.37%)}	_{🟩-0.014s (-13.58%)}	_0.074s	_0.132s	_{p=0.011 n=20}
_{Check Time}	_{5.922s (± 0.53%)}	_{5.840s (± 0.65%)}	_{-0.081s (- 1.38%)}	_5.694s	_6.102s	_{p=0.000 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{6.288s (± 0.53%)}	_{6.193s (± 0.64%)}	_{-0.095s (- 1.51%)}	_6.043s	_6.454s	_{p=0.000 n=20}
_{tanstack-router - native}
_Errors	₁	₁	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_570,149	_570,149	_~	_~	_~	_{p=1.000 n=20}
_Types	_396,551	_396,551	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{315,310k (± 0.02%)}	_{315,346k (± 0.01%)}	_~	_315,124k	_315,511k	_{p=0.588 n=20}
_{Memory Allocs}	_{4,331,149 (± 0.16%)}	_{4,335,398 (± 0.19%)}	_~	_4,312,357	_4,375,478	_{p=0.529 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.039s (± 4.33%)}	_{0.039s (± 4.46%)}	_~	_0.031s	_0.046s	_{p=0.888 n=20}
_{Bind Time}	_{0.012s (±10.24%)}	_{0.012s (±11.75%)}	_~	_0.010s	_0.021s	_{p=0.112 n=20}
_{Check Time}	_{0.460s (± 1.04%)}	_{0.453s (± 0.89%)}	_{-0.008s (- 1.66%)}	_0.440s	_0.472s	_{p=0.025 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.530s (± 0.94%)}	_{0.523s (± 0.85%)}	_{-0.007s (- 1.38%)}	_0.506s	_0.539s	_{p=0.030 n=20}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_231,607	_231,607	_~	_~	_~	_{p=1.000 n=20}
_Types	_181,163	_181,163	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{190,841k (± 0.02%)}	_{190,860k (± 0.02%)}	_~	_190,759k	_191,008k	_{p=0.551 n=20}
_{Memory Allocs}	_{1,310,092 (± 0.02%)}	_{1,309,904 (± 0.02%)}	_~	_1,308,513	_1,311,343	_{p=0.402 n=20}
_{Config Time}	_0.000s	_{0.000s (±208.60%)}	_~	_0.000s	_0.001s	_{p=1.000 n=20}
_{Parse Time}	_{0.049s (± 3.54%)}	_{0.048s (± 6.87%)}	_~	_0.041s	_0.074s	_{p=0.248 n=20}
_{Bind Time}	_{0.023s (± 5.68%)}	_{0.024s (± 6.91%)}	_~	_0.018s	_0.030s	_{p=0.090 n=20}
_{Check Time}	_{0.339s (± 2.43%)}	_{0.340s (± 3.27%)}	_~	_0.314s	_0.430s	_{p=0.899 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.418s (± 2.14%)}	_{0.419s (± 2.70%)}	_~	_0.392s	_0.507s	_{p=0.899 n=20}
_{vscode - native}
_Errors	₁₁	₁₁	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_7,866,033	_7,866,033	_~	_~	_~	_{p=1.000 n=20}
_Types	_4,606,120	_4,606,120	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{5,285,624k (± 0.01%)}	_{5,285,881k (± 0.01%)}	_~	_5,283,300k	_5,289,429k	_{p=0.698 n=20}
_{Memory Allocs}	_{59,221,556 (± 0.01%)}	_{59,230,395 (± 0.02%)}	_~	_59,205,706	_59,316,721	_{p=0.659 n=20}
_{Config Time}	_{0.034s (± 0.94%)}	_{0.033s (± 0.43%)}	_{-0.001s (- 1.49%)}	_0.033s	_0.034s	_{p=0.010 n=20}
_{Parse Time}	_{0.907s (± 1.16%)}	_{0.896s (± 1.02%)}	_~	_0.855s	_0.940s	_{p=0.250 n=20}
_{Bind Time}	_{0.295s (± 1.73%)}	_{0.286s (± 1.30%)}	_{-0.008s (- 2.83%)}	_0.280s	_0.316s	_{p=0.000 n=20}
_{Check Time}	_{7.174s (± 0.56%)}	_{7.087s (± 0.37%)}	_{-0.087s (- 1.22%)}	_6.987s	_7.194s	_{p=0.000 n=20}
_{Emit Time}	_{2.081s (± 5.06%)}	_{2.061s (± 4.69%)}	_{-0.020s (- 0.94%)}	_1.944s	_2.714s	_{p=0.018 n=20}
_{Total Time}	_{10.548s (± 0.81%)}	_{10.422s (± 0.86%)}	_{-0.126s (- 1.19%)}	_10.253s	_11.005s	_{p=0.000 n=20}
_{webpack - native}
_Errors	₆₁₅	₆₁₅	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_887,312	_887,312	_~	_~	_~	_{p=1.000 n=20}
_Types	_626,023	_626,023	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{647,537k (± 0.02%)}	_{647,529k (± 0.02%)}	_~	_647,003k	_648,005k	_{p=0.841 n=20}
_{Memory Allocs}	_{6,068,449 (± 0.06%)}	_{6,066,458 (± 0.05%)}	_~	_6,057,166	_6,081,404	_{p=0.429 n=20}
_{Config Time}	_0.004s	_0.004s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.121s (± 1.80%)}	_{0.122s (± 1.73%)}	_~	_0.114s	_0.132s	_{p=0.577 n=20}
_{Bind Time}	_{0.041s (± 9.96%)}	_{0.039s (± 8.04%)}	_~	_0.033s	_0.055s	_{p=0.216 n=20}
_{Check Time}	_{1.020s (± 1.20%)}	_{1.012s (± 1.12%)}	_~	_0.972s	_1.057s	_{p=0.387 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{1.208s (± 1.02%)}	_{1.200s (± 1.09%)}	_~	_1.163s	_1.251s	_{p=0.344 n=20}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=20}
_Symbols	_644,330	_644,330	_~	_~	_~	_{p=1.000 n=20}
_Types	_392,175	_392,175	_~	_~	_~	_{p=1.000 n=20}
_{Memory Used}	_{347,007k (± 0.03%)}	_{347,033k (± 0.03%)}	_~	_346,723k	_347,471k	_{p=0.820 n=20}
_{Memory Allocs}	_{4,000,995 (± 0.08%)}	_{4,003,907 (± 0.13%)}	_~	_3,984,904	_4,039,848	_{p=0.301 n=20}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=20}
_{Parse Time}	_{0.062s (± 3.36%)}	_{0.062s (± 3.53%)}	_~	_0.057s	_0.074s	_{p=0.712 n=20}
_{Bind Time}	_{0.021s (±11.37%)}	_{0.019s (± 8.53%)}	_~	_0.016s	_0.027s	_{p=0.277 n=20}
_{Check Time}	_{0.427s (± 0.99%)}	_{0.416s (± 0.80%)}	_{-0.011s (- 2.51%)}	_0.404s	_0.435s	_{p=0.000 n=20}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=20}
_{Total Time}	_{0.516s (± 1.04%)}	_{0.504s (± 1.02%)}	_{-0.012s (- 2.30%)}	_0.483s	_0.524s	_{p=0.003 n=20}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
arktype - native
class-transformer - native
effect - native
mui-docs - native
sentry - native
social-app - native
strada-build-src - native
strada-compiler - native
t3code-server - native
tanstack-router - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₂₀
_Baseline	_baseline	₂₀

Developer Information:

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Jake Bailey (jakebailey) · 2026-11-05T18:49:00Z

Okay, it's seemingly a little bit

Copilot AI balanced review requested due to automatic review settings November 5, 2026 17:45

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Jake Bailey (jakebailey) marked this pull request as draft November 5, 2026 17:46

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Jake Bailey (jakebailey) added the Domain: Performance Reports of unusually slow behavior label Nov 5, 2026

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Skip heap profile sampling unless profiling - #65338

Skip heap profile sampling unless profiling#65338
Jake Bailey (jakebailey) wants to merge 1 commit into
microsoft:mainfrom
jakebailey:perf/mem-profile-rate

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