From: Nathan Bossart <nathan@postgresql.org>
Date: Tue, 2 Apr 2024 15:32:49 +0000 (-0500)
Subject: Avoid function call overhead of pg_popcount() in syslogger.c.
X-Git-Tag: REL_17_BETA1~445
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=4133c1f45c54f0e52b4bb758f67af78951930e43;p=postgresql.git

Avoid function call overhead of pg_popcount() in syslogger.c.

Instead of calling the pg_popcount() function for a single byte, we
can look up the value in the pg_number_of_ones array.

Discussion: https://postgr.es/m/20240401221117.GB2362108%40nathanxps13
---

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 08efe74cc91..437947dbb9d 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -898,7 +898,7 @@ process_pipe_input(char *logbuffer, int *bytes_in_logbuffer)
 		if (p.nuls[0] == '\0' && p.nuls[1] == '\0' &&
 			p.len > 0 && p.len <= PIPE_MAX_PAYLOAD &&
 			p.pid != 0 &&
-			pg_popcount((char *) &dest_flags, 1) == 1)
+			pg_number_of_ones[dest_flags] == 1)
 		{
 			List	   *buffer_list;
 			ListCell   *cell;