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Update PG_CACHE_LINE_SIZE description.

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PG_CACHE_LINE_SIZE was originally only used in xlog.c, but this hasn't
been true for a very long time and is now wildly used, so modify its
description to not mention any explicit source code file.

Author: Julien Rouhaud
Discussion: https://www.postgresql.org/message-id/20230701074936.p3qcssl4t7murt2q@jrouhaud
This commit is contained in:
Heikki Linnakangas 2023-07-03 11:56:30 +03:00
parent 9945750ae0
commit dc6070bf5d
1 changed files with 7 additions and 7 deletions
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14
src/include/pg_config_manual.h
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@ -217,13 +217,13 @@
#define DEFAULT_EVENT_SOURCE "PostgreSQL"
/*
* Assumed cache line size. This doesn't affect correctness, but can be used
* for low-level optimizations. Currently, this is used to pad some data
* structures in xlog.c, to ensure that highly-contended fields are on
* different cache lines. Too small a value can hurt performance due to false
* sharing, while the only downside of too large a value is a few bytes of
* wasted memory. The default is 128, which should be large enough for all
* supported platforms.
* Assumed cache line size. This doesn't affect correctness, but can be used
* for low-level optimizations. This is mostly used to pad various data
* structures, to ensure that highly-contended fields are on different cache
* lines. Too small a value can hurt performance due to false sharing, while
* the only downside of too large a value is a few bytes of wasted memory.
* The default is 128, which should be large enough for all supported
* platforms.
*/
#define PG_CACHE_LINE_SIZE 128