On 05.01.2013 11:35, Philip Martin wrote: > Branko Čibej <br...@wandisco.com> writes: > >> * The BDB backend is an order of magnitude slower on trunk than FSFS >> o timing parallel "make check" on my 4x4-core i7+ssd mac: >> + FSFS: real 7m33.213s, user 19m8.075s, sys 10m54.739s >> + BDB: real 35m17.766s, user 15m28.395s, sys 11m58.824s > I don't see that behaviour. On my machine with 1x2 Core2 Duo, Linux and > SSD: > > FSFS: real 12m42.383s, user 7m37.557s, sys 5m58.534s > BDB: real 11m30.895s, user 8m14.603s, sys 5m45.358s
Interesting that i's that much slower on the Mac. But considering my numbers: * FSFS: real 7m33.213s, user 19m8.075s, sys 10m54.739s * BDB: real 35m17.766s, user 15m28.395s, sys 11m58.824s Notice that the sys and user times are comparable, yet real-time is an order of magnitude higher with BDB. Also, in the FSFS case, real time is actually lower than user or sys time, which makes sense for parallel tests. I interpret that as meaning that FSFS parallelizes (across different processes) better than BDB, and that BDB spends most of its time twiddling its thumbs waiting for I/O. > I don't think either your results or mine indicate anything about the > relative performance of the backends as all the repositories in the > testsuite are far too small. That's true. Of course, the numbers are only one data point, personally I think the long-term maintenance costs are much more important. One thing I /don't/ know is what percentage of the Subversion installed base (in both number of repositories and repository size) falls to BDB. Does anyone have any idea about that? -- Brane -- Branko Čibej Director of Subversion | WANdisco | www.wandisco.com
