Topic: Experimental pre-0.8 builds for testing - page 6. (Read 19876 times)

Sounds great, keep up the good work And no need to rush

When someone implements an improvement. I plan to have a look at this myself soon, but no promises.


It still needs a lot of testing, and several things are missing before we can have a new stable release.

Do you happen to know when the way the blockchain gets downloaded gets changed? Perhaps even downloading in parallel from multiple peers?

Edit: And is there an ETA for the 0.8 release? I'm so looking forward to all these great changes to hit to main release

If you're syncing from the network even if your own connection is fast you're subject to luck of the draw on which peers you pull from. This is one reason Pieter was suggesting loadblock runs above.

I downloaded the bitcoin-0.7.1-244-g3ccb06f-win32-setup.exe, installed on my test laptop (Dual core 2GHz Intel, 2GB DDR, with XP) and, without any other extra parameters, it took ~6:40 hours to process 193395 blocks of transaction history. The cpu use was so far ~ 25%.

After this I had to restart the client (the download apparently stopped) and the cpu usage increased to ~75% (sometimes 97-99%). Later it dropped to ~65% while download speed was ~ 250 KB/s.

A new restart was needed after 9:43 hours. The download bar at the bottom of the window disappeared, hopefully this won't scare a regular user.

Finally, the block chain fully synchronized after ~13:00 hours...


I have to admit I expected a way shorter time than that.

Disclaimer: your mileage may vary.

turbo build just crashed on win 7 64. ran for quite a few hours and then came weirdo "this program requested visual studio runtime library to terminate it in an unusual way"-or something-message, which i successfully closed by reflex 

was doing normal blockchain download stuck around 93% with 30 connections.

Yes, before reindex, i'm running pre0.8 1025build version, synced.

Laptop:  Intel Core i3, 4GB ram

Were you already synced with 0.8 before attempting that reindex?  If so that was horribly slow.

Starting from an empty ~/.bitcoin directory (having only bootstrap.dat and a bitcoin.conf with an rpc password) and running this:


Took 1 hour 57 to reach height 211494 when at that moment the latest block was 211518. As soon as 211519 was found some minutes later the remaining blocks were processed/downloaded/whatever.

4 CPU cores. RAM usage reached 420 Mb RSS, after synchronization it ended up at 375 Mb. Restarting the daemon leaves it at 130 Mb. I've never used -dbcache until now, if that matters. Usual RAM usage until now was 80-90 Mb just after starting, then going up slowly as days passed (like in, 130 Mb after ~10 days).

"C:\Program Files\Bitcoin\bitcoin-qt.exe" -reindex -par=4 -dbcache=500 -logtimestamps -benchmark

3h22m
@ Windows7

Multithreading seems to be working well!

This is v0.7.1-244-g3ccb06f-beta starting from a completely bare directory, downloading the blockchain from a peer on the same LAN to remove internet connection speed as a factor.


Again with a larger cache.

Hello all,

I've uploaded a new set of builds of bitcoind/Bitcoin-Qt to my builds page. The new "turbo" build is based on current master on git, plus some more experimental patches (Hal Finney's optimized secp256k1 code, and parallel script verification). The source code for these can be found here (.tgz archive here).

Disclaimer: don't use these for any serious stuff - I am not responsible for destroyed wallets or exploded CPU's.

Testing of these is very welcome.

As the most invasive change is in the block/transaction validation system, this is the most interesting part to test. I am very interested in reports about speed, CPU usage, memory usage, ... during initial block synchronization, in particular on Windows systems. Obviously, crashes or other unexpected behaviour is even more important.

As these builds use the new 0.8 database code ("ultraprune", as I called it before), they will not use the existing block files/database from 0.7.2 or earlier. There are several ways to import the data:

• Put bootstrap.dat in your data directory.
• Start the program with options -loadblock=path/to/old/blk0001.dat -loadblock=path/to/old/blk0002.dat.
• If you already have a full 0.8 database (perhaps from a next-test build), you can use the new -reindex option to rebuild your index from scratch, redoing the block validation process, reusing the block data you already have on disk.
• Obviously, you can also just let it synchronize from network, but as the current block-fetch logic is somewhat of a hack, you may get unlucky, and hit a slow peer, or have downloads that stop for long periods of time. It is advised to use -connect=IP to connect to a single fast peer (you can use my server, 178.18.90.41, for this purpose if needed) for that.

As these builds use parallel script verification (only enabled after block 193000, the last checkpoint), you may wish to control how many threads are used (don't use more than the number of CPU cores you have). By default, it will try to autodetect, but you can use the -par=N option to select the number of threads. One interesting thing you can test is comparing -par=1 with higher numbers, and check the speedup (in particular of the blocks after 193000).

Other options which may be useful to play with:

• -dbcache=N tweaks the amount of cache used. N is a number in megabytes (default is 25), but higher numbers may result in significant speedups.
• -logtimestamps adds timestamps to the output in the debug.log file, which may be very useful to compare speed.
• -benchmark produces detailed timing information during block validation (not very accurate on Windows, unfortunately).