Re: Indentation and gc

[Ihor Radchenko]

Eli Zaretskii <eliz@gnu.org> writes:

> I'm talking about basis for the 0.7% figure.

I used 0.7%*RAM because total RAM is the only reasonable metrics. What
else can we use to avoid memory over-consumption on low-end machines?

Of course, I used implicit assumption that memory usage will scale with
gc-cons-threshold linearly. IMHO, it is a safe assumption - the real
memory usage increase is slower than linear. For example, see my Emacs
loading data for different threshold values:

| gc-cons-threshold | memory-limit | gcs-done |   gc-elapsed | gc time     |
| 1Mb               |       523704 |      394 | 25.809423617 | 0.065506151 |
| 2Mb               |        +9624 |      210 |  13.41456755 | 0.063878893 |
| 4Mb               |        +1224 |      109 |  6.400488833 | 0.058720081 |
| 8Mb               |        +3164 |       63 |  3.223383144 | 0.051164812 |
| 16Mb              |        +5532 |       37 |  1.757097776 | 0.047489129 |
| 32Mb              |       +20264 |       25 |  0.995694149 | 0.039827766 |
| 64Mb              |       +59860 |       19 |  0.624039941 | 0.032844207 |
| 128Mb             |      +115356 |       16 |   0.42626893 | 0.026641808 |
| 256Mb             |      +171176 |       14 |  0.277912281 | 0.019850877 |
| 512Mb             |      +332148 |       12 |  0.122461442 | 0.010205120 |

Also, see the attached graph.

benchmark-gc.png
Description: PNG image

The 0.7% is to ensure safe 800kb lower bound on low-end computers.

> Anyway, how about if you try running with the threshold you think we
> should adopt, and report back after a month or so, say?

I am using 250Mb threshold for the last 3 years or so.
GCs are sometimes noticeable, but not annoying:

- gc-elapsed 297 sec / gcs-done 290 -> ~1 sec per GC
- Emacs uptime 2 days 5 hours 21 minutes -> 1 GC per 10 minutes
- memory-limit 6,518,516, stable
  37x from Emacs -Q memory-limit
  10x from Emacs loading with my init.el

-- 
Ihor Radchenko // yantar92,
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