build: allow specification of custom cargo config for kernel compilation

[fogti]

Of course, this will subsequently require a patch of the cargo build script of the hermit crate, in order to report the env var and the file it points to as a rebuild dependency.

[github-actions]

Benchmark Results

Benchmark	Current: 804a15a	Previous: 06380c9	Performance Ratio
startup_benchmark Build Time	113.42 s	111.30 s	1.02
startup_benchmark File Size	0.91 MB	0.91 MB	1.00
Startup Time - 1 core	0.91 s (±0.04 s)	0.94 s (±0.02 s)	0.97
Startup Time - 2 cores	0.91 s (±0.03 s)	0.94 s (±0.02 s)	0.98
Startup Time - 4 cores	0.93 s (±0.03 s)	0.95 s (±0.03 s)	0.98
multithreaded_benchmark Build Time	112.70 s	111.47 s	1.01
multithreaded_benchmark File Size	1.01 MB	1.01 MB	1.00
Multithreaded Pi Efficiency - 2 Threads	91.46 % (±8.14 %)	88.67 % (±8.42 %)	1.03
Multithreaded Pi Efficiency - 4 Threads	44.28 % (±3.32 %)	44.22 % (±3.59 %)	1.00
Multithreaded Pi Efficiency - 8 Threads	25.76 % (±2.15 %)	25.40 % (±2.21 %)	1.01
micro_benchmarks Build Time	298.05 s	298.11 s	1.00
micro_benchmarks File Size	1.02 MB	1.02 MB	1.00
Scheduling time - 1 thread	186.96 ticks (±33.49 ticks)	174.36 ticks (±24.88 ticks)	1.07
Scheduling time - 2 threads	105.37 ticks (±22.05 ticks)	102.58 ticks (±17.96 ticks)	1.03
Micro - Time for syscall (getpid)	9.65 ticks (±5.13 ticks)	12.86 ticks (±5.49 ticks)	0.75
Memcpy speed - (built_in) block size 4096	59833.27 MByte/s (±42726.75 MByte/s)	54678.51 MByte/s (±39898.38 MByte/s)	1.09
Memcpy speed - (built_in) block size 1048576	13496.11 MByte/s (±10998.94 MByte/s)	13904.98 MByte/s (±11992.20 MByte/s)	0.97
Memcpy speed - (built_in) block size 16777216	9918.28 MByte/s (±8023.63 MByte/s)	9871.01 MByte/s (±8007.61 MByte/s)	1.00
Memset speed - (built_in) block size 4096	59758.96 MByte/s (±42690.05 MByte/s)	54863.90 MByte/s (±40016.65 MByte/s)	1.09
Memset speed - (built_in) block size 1048576	13722.26 MByte/s (±11098.12 MByte/s)	14267.94 MByte/s (±12189.39 MByte/s)	0.96
Memset speed - (built_in) block size 16777216	10182.17 MByte/s (±8183.88 MByte/s)	10102.41 MByte/s (±8139.80 MByte/s)	1.01
Memcpy speed - (rust) block size 4096	52296.54 MByte/s (±38422.16 MByte/s)	53878.52 MByte/s (±40203.47 MByte/s)	0.97
Memcpy speed - (rust) block size 1048576	13342.32 MByte/s (±11045.32 MByte/s)	15011.79 MByte/s (±13075.07 MByte/s)	0.89
Memcpy speed - (rust) block size 16777216	10003.24 MByte/s (±8090.56 MByte/s)	9892.57 MByte/s (±8037.27 MByte/s)	1.01
Memset speed - (rust) block size 4096	52390.48 MByte/s (±38460.87 MByte/s)	54652.16 MByte/s (±40703.26 MByte/s)	0.96
Memset speed - (rust) block size 1048576	13582.43 MByte/s (±11158.36 MByte/s)	15339.99 MByte/s (±13218.29 MByte/s)	0.89
Memset speed - (rust) block size 16777216	10223.12 MByte/s (±8210.05 MByte/s)	10120.58 MByte/s (±8166.06 MByte/s)	1.01
alloc_benchmarks Build Time	294.54 s	292.86 s	1.01
alloc_benchmarks File Size	0.98 MB	0.98 MB	1.00
Allocations - Allocation success	100.00 %	100.00 %	1
Allocations - Deallocation success	100.00 %	100.00 %	1
Allocations - Pre-fail Allocations	100.00 %	100.00 %	1
Allocations - Average Allocation time	11899.12 Ticks (±862.76 Ticks)	22133.78 Ticks (±874.32 Ticks)	0.54
Allocations - Average Allocation time (no fail)	11899.12 Ticks (±862.76 Ticks)	22133.78 Ticks (±874.32 Ticks)	0.54
Allocations - Average Deallocation time	2509.92 Ticks (±151.85 Ticks)	3223.16 Ticks (±1689.20 Ticks)	0.78
mutex_benchmark Build Time	296.53 s	295.42 s	1.00
mutex_benchmark File Size	1.02 MB	1.02 MB	1.00
Mutex Stress Test Average Time per Iteration - 1 Threads	37.50 ns (±4.48 ns)	37.08 ns (±4.18 ns)	1.01
Mutex Stress Test Average Time per Iteration - 2 Threads	30.22 ns (±3.60 ns)	30.58 ns (±3.16 ns)	0.99

This comment was automatically generated by workflow using github-action-benchmark.