I have been investigating general performance today and was very pleasantly surprised to see the new version of ruby (2.6.1) both reduces memory usage AND speeds up Discourse.
In particular, looking at Discourse bench:
RSS is reduced from 293332 to 262140 bytes!
Median request time
| route | 2.5.3 (ms) | 2.6.1 (ms) | change |
|---|---|---|---|
| categories | 41 | 39 | 4.88% |
| home | 46 | 43 | 6.52% |
| topic | 54 | 48 | 11.11% |
| categories_admin | 70 | 65 | 7.14% |
| home_admin | 72 | 67 | 6.94% |
| topic_admin | 82 | 77 | 6.10% |
75th percentile
| route | 2.5.3 | 2.6.1 | change |
|---|---|---|---|
| categories | 42 | 41 | 2.38% |
| home | 50 | 46 | 8.00% |
| topic | 59 | 51 | 13.56% |
| categories_admin | 75 | 76 | -1.33% |
| home_admin | 78 | 77 | 1.28% |
| topic_admin | 85 | 83 | 2.35% |
90th percentile
| route | 2.5.3 | 2.6.1 | change |
|---|---|---|---|
| categories | 49 | 52 | -6.12% |
| home | 56 | 56 | 0.00% |
| topic | 62 | 61 | 1.61% |
| categories_admin | 82 | 81 | 1.22% |
| home_admin | 84 | 82 | 2.38% |
| topic_admin | 93 | 92 | 1.08% |
99th percentile
| route | 2.5.3 | 2.6.1 | change |
|---|---|---|---|
| categories | 58 | 81 | -39.66% |
| home | 81 | 108 | -33.33% |
| topic | 76 | 88 | -15.79% |
| categories_admin | 105 | 132 | -25.71% |
| home_admin | 115 | 132 | -14.78% |
| topic_admin | 123 | 142 | -15.45% |
It is going to take us a bit of time prior to upgrading to 2.6.1, we will probably switch over in 2-3 months. We also still need to validate these results on rubybench.org. That said these initial results are incredibly promising.
We will be usually expecting 7% improvement however our 1 in 100 requests will suffer a 15-40% slowdown. My interpretation of the results is that the runtime has gotten faster, but the major GC time has become a bit slower.