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geth help has:
VIRTUAL MACHINE OPTIONS:
--jitvm Enable the JIT VM
The impact of --jitvm has been unanswered and I'm looking for answers to these 3 specifically:
How much faster is geth --fast --jitvm than just geth --fast?
How much faster is geth --fast --cache=1024 --jitvm than just geth --fast --cache=1024?
How much faster is geth --jitvm than just geth?
geth 1.5 is way faster but there are problems to keep connections with peers. When there is a high latency, it removes agressively the peer connection. I use the patch 2630 from Péter Szilágyi in the 1.5 version.
benchmarks done on OS X with 37320qm 16Go ram 1To SSD with geth 1.4.4 (stable):
___________________________________________________________________
| Option | Disk Used | Time | Disk Written |
|-----------------------------|-----------|-------|---------------|
| | 21GB | 5h00 | 1TB |
| --fast | 4.1GB | 1h00 | 100GB |
| --cache 1024 --jitvm | 21GB | 6h00 | 1TB |
| --fast --cache 1024 --jitvm | ???? | | |
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Note: network is very unstable today (for the --cache and --jitvm benchs), other tests were done when network worked better. There are many times where geth loose all peers. But not sure there are great benefices with --jitvm or --cache.
benchmarks done on OS X with 37320qm 16Go ram 1To SSD:
___________________________________________________________________
| Option | Disk Used | Time | Disk Written |
|-----------------------------|-----------|-------|---------------|
| | 21GB | | |
| --cache 1024 --jitvm | 21GB | 4h10 | 543GB |
| --fast | 4.1GB | 25m | 52GB |
| --fast --cache 1024 --jitvm | 4.1GB | | |
-------------------------------------------------------------------
The results should be the same as the 1.5.0 version. The difference is probably due to network connections with other peers.
benchmarks done on OS X with 37320qm 16Go ram 1To HDD 5400tr/min:
___________________________________________________________________
| Option | Disk Used | Time | Disk Written |
|-----------------------------|-----------|-------|---------------|
| | | | |
| --cache 1024 --jitvm | | 20h | 450GB |
| --fast | 4.1GB | | 60GB |
| --fast --cache 1024 --jitvm | 4.1GB | 4h15m | 60GB |
------------------------------------------------------------------
The HDD benchmarks is very low. It is way slower. If you have 8Go of ram, create a RAM disk to do the --fast & --datadir on it and copy the results in your ethereum directory.
benchmarks done on OS X with 37320qm 16Go ram 1To SSD with geth 1.5.0 (unstable) the 4 june 2016:
__________________________________________________________________
| Option | Disk Used | Time | Disk Written |
|-----------------------------|-----------|------|---------------|
| | 21GB | | 450GB |
| --cache 1024 --jitvm | 21GB |3h01 | 450GB |
| --fast | 4.1GB |20m06 | 52GB |
| --fast --cache 1024 --jitvm | 4.1GB |21m10s| 52GB |
------------------------------------------------------------------
This version 1.5 is very stable. I made few full syncs and fast synchs and found the same results +/- few %. Good Work
Note 1: for the --fast flag, the --jitvm and the --cache show no gain.
Note 2: the import operation is similar to a full synchronization: 3h00
I did a few bench by myself and found as well that there is no significant impact of --jitvm. And I agree that geth 1.5.0 with patch is way faster.:)
Note: the 1.4.6 version has these patchs and synchronize quickly
geth removedbb) close all software that uses bandwith (torrent addicts :) c) run the command d) how you time it ? d) is critical, I can't think of a way to get the timestamp whn the db is synced