Subject: Re: [boost] [review] The review of Boost.DoubleEnded starts today: September 21 - September 30
From: Thorsten Ottosen (tottosen_at_[hidden])
Date: 2017-10-02 17:30:17
Hi,
Some more points to consider. I tried comparing
push_back/unsafe_push_back a little. I don't see any performance speedup
on my system if the loop body is just the push_back. If I make the loop
a little more complicated than just a push_back, I get some differences:
32 bit:
boost::vector::push_back vs devector::unsafe_push_back
10E3 29.0508 24.8578
10E4 26.9987 22.7853
10E5 26.9468 22.3659
10E6 26.9766 22.3562
10E7 27.1064 22.5215
64 bit:
10E3 28.6106 24.2881
10E4 27.9322 23.6613
10E5 28.0182 23.3318
10E6 28.0493 23.3803
10E7 28.1458 23.5394
32 bit:
boost::deque::push_back vs batch_deque::unsafe_push_back
10E3 34.803 45.6774
10E4 36.0686 46.3888
10E5 36.7773 48.6228
10E6 40.7754 49.6144
10E7 43.1134 49.1949
64 bit:
10E3 33.5997 30.0433
10E4 35.5992 32.8985
10E5 34.4685 48.9641
10E6 40.7974 48.6893
10E7 43.2836 48.9001
I'm not 100% sure why batch_deque is so much slower, but looking a
little at the assembler, it seems that going from an iterator to a
pointer may be expensive because the batch_deque::iterator uses a
segment pointer and an index. (normal push_back in batch_deque therefore
also appears somewhat slower than in boost::deque).
kind regards
Thorsten