oragono mkcerts should generate a 2048-bit RSA certificate #898
Description
The current default of an ECDSA certificate is extremely slow, for unclear reasons. This was one of the causes of #894. I tested with a self-signed 2048-bit RSA certificate and it's between 3x and 10x faster on Go 1.14.1:
# ecdsa
(pprof) top 40
Showing nodes accounting for 3.98s, 85.04% of 4.68s total
Dropped 133 nodes (cum <= 0.02s)
Showing top 40 nodes out of 159
flat flat% sum% cum cum%
1.06s 22.65% 22.65% 1.71s 36.54% math/big.nat.divBasic
0.42s 8.97% 31.62% 0.42s 8.97% math/big.addMulVVW
0.28s 5.98% 37.61% 0.28s 5.98% math/big.subVV
0.19s 4.06% 41.67% 0.19s 4.06% math/big.mulAddVWW
0.18s 3.85% 45.51% 0.24s 5.13% runtime.scanobject
0.17s 3.63% 49.15% 0.17s 3.63% runtime.futex
0.12s 2.56% 51.71% 0.68s 14.53% runtime.mallocgc
0.12s 2.56% 54.27% 0.12s 2.56% runtime.memclrNoHeapPointers
0.12s 2.56% 56.84% 0.12s 2.56% runtime.procyield
0.11s 2.35% 59.19% 0.11s 2.35% runtime.findObject
0.09s 1.92% 61.11% 0.49s 10.47% math/big.basicMul
0.09s 1.92% 63.03% 0.09s 1.92% runtime.nextFreeFast (inline)
0.08s 1.71% 64.74% 0.08s 1.71% math/big.shlVU
0.07s 1.50% 66.24% 0.07s 1.50% syscall.Syscall
0.06s 1.28% 67.52% 0.07s 1.50% math/big.nat.norm
0.06s 1.28% 68.80% 0.06s 1.28% math/big.shrVU
0.06s 1.28% 70.09% 0.22s 4.70% runtime.gcWriteBarrier
0.06s 1.28% 71.37% 0.06s 1.28% runtime.markBits.isMarked (inline)
0.05s 1.07% 72.44% 0.05s 1.07% runtime.epollwait
0.05s 1.07% 73.50% 0.05s 1.07% runtime.usleep
0.05s 1.07% 74.57% 0.16s 3.42% runtime.wbBufFlush1
0.04s 0.85% 75.43% 0.62s 13.25% math/big.nat.make (inline)
0.03s 0.64% 76.07% 2.42s 51.71% crypto/elliptic.(*CurveParams).doubleJacobian
# 2048-bit rsa
(pprof) top 40
Showing nodes accounting for 1.28s, 100% of 1.28s total
Showing top 40 nodes out of 176
flat flat% sum% cum cum%
0.62s 48.44% 48.44% 0.62s 48.44% math/big.addMulVVW
0.18s 14.06% 62.50% 0.77s 60.16% math/big.nat.montgomery
0.10s 7.81% 70.31% 0.10s 7.81% syscall.Syscall
0.03s 2.34% 72.66% 0.80s 62.50% math/big.nat.expNNMontgomery
0.03s 2.34% 75.00% 0.03s 2.34% math/big.subVV
0.03s 2.34% 77.34% 0.03s 2.34% runtime.nextFreeFast (inline)
0.02s 1.56% 78.91% 0.02s 1.56% crypto/sha256.block
0.02s 1.56% 80.47% 0.04s 3.12% math/big.nat.divBasic
0.02s 1.56% 82.03% 0.02s 1.56% runtime.futex
0.02s 1.56% 83.59% 0.02s 1.56% runtime.write1
0.02s 1.56% 85.16% 0.02s 1.56% vendor/golang.org/x/crypto/curve25519.ladderstep
0.01s 0.78% 85.94% 0.01s 0.78% crypto/aes.(*gcmAsm).Open
0.01s 0.78% 86.72% 0.01s 0.78% crypto/tls.(*certificateMsgTLS13).unmarshal
0.01s 0.78% 87.50% 0.01s 0.78% fmt.(*pp).doPrintf
0.01s 0.78% 88.28% 0.06s 4.69% github.com/oragono/oragono/irc.(*Socket).performWrite
0.01s 0.78% 89.06% 0.01s 0.78% indexbytebody
0.01s 0.78% 89.84% 0.02s 1.56% math/big.(*Int).Add
0.01s 0.78% 90.62% 0.01s 0.78% math/big.greaterThan (inline)
0.01s 0.78% 91.41% 0.01s 0.78% math/big.nat.mulAddWW
0.01s 0.78% 92.19% 0.10s 7.81% net.(*conn).Write