mirror of
https://github.com/jemalloc/jemalloc.git
synced 2026-07-19 07:07:18 +03:00
de9ad1450b
Convert the production source files in src/ (69 .c/.cpp) and test/jemalloc_test.h.in to list the headers they actually use, then delete the umbrella. Three consolidated headers (peak_event.h, prof_sys.h, sz.h) also gain explicit transitive includes. Every translation unit now declares what it uses. A missing include now fails at the failing file rather than silently working because something upstream pulled in the world.
28 lines
1.4 KiB
C
28 lines
1.4 KiB
C
#include "jemalloc/internal/jemalloc_preamble.h"
|
|
|
|
#include "jemalloc/internal/ticker.h"
|
|
|
|
/*
|
|
* To avoid using floating point math down core paths (still necessary because
|
|
* versions of the glibc dynamic loader that did not preserve xmm registers are
|
|
* still somewhat common, requiring us to be compilable with -mno-sse), and also
|
|
* to avoid generally expensive library calls, we use a precomputed table of
|
|
* values. We want to sample U uniformly on [0, 1], and then compute
|
|
* ceil(log(u)/log(1-1/nticks)). We're mostly interested in the case where
|
|
* nticks is reasonably big, so 1/log(1-1/nticks) is well-approximated by
|
|
* -nticks.
|
|
*
|
|
* To compute log(u), we sample an integer in [1, 64] and divide, then just look
|
|
* up results in a table. As a space-compression mechanism, we store these as
|
|
* uint8_t by dividing the range (255) by the highest-magnitude value the log
|
|
* can take on, and using that as a multiplier. We then have to divide by that
|
|
* multiplier at the end of the computation.
|
|
*
|
|
* The values here are computed in src/ticker.py
|
|
*/
|
|
|
|
const uint8_t ticker_geom_table[1 << TICKER_GEOM_NBITS] = {254, 211, 187, 169,
|
|
156, 144, 135, 127, 120, 113, 107, 102, 97, 93, 89, 85, 81, 77, 74, 71, 68,
|
|
65, 62, 60, 57, 55, 53, 50, 48, 46, 44, 42, 40, 39, 37, 35, 33, 32, 30, 29,
|
|
27, 26, 24, 23, 21, 20, 19, 18, 16, 15, 14, 13, 12, 10, 9, 8, 7, 6, 5, 4, 3,
|
|
2, 1, 0};
|