[pkgsrc/trunk]: pkgsrc/lang/php71 Performance fix for uniqid()

[manu <manu%pkgsrc.org@localhost>]

details:   https://anonhg.NetBSD.org/pkgsrc/rev/a0d5488bc66e
branches:  trunk
changeset: 365459:a0d5488bc66e
user:      manu <manu%pkgsrc.org@localhost>
date:      Mon Jul 17 14:10:08 2017 +0000

description:
Performance fix for uniqid()

PHP uniqid() relies on microsecond-precise system clock to produce an
unique identifier. In order to avoid  using the same value, it first
calls usleep(1) to wait for the next microsecond.

Unfortunately, usleep() specification says "The suspension time may be
longer than requested due to the scheduling of other activity by the
system." Indeed, the pause may as as long as an entire execution slice,
causing a uniqid() call to last more than 10 ms.

This is fixed by replacing the usleep() call by time polling using
gettimeofday() until the microscecond change. Since the getttimeoday()
system call lasts around a microsecond, only a small time is wasted
calling  multiple gettimeofday. On the benefit side, uniqid() performance
in increased 10000 fold without changing its behavior.

Submitted upstream as https://bugs.php.net/bug.php?id=74851

diffstat:

 lang/php71/distinfo                            |   3 +-
 lang/php71/patches/patch-ext_standard_uniqid.c |  62 ++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletions(-)

diffs (83 lines):

diff -r 4912c512ec5a -r a0d5488bc66e lang/php71/distinfo
--- a/lang/php71/distinfo       Mon Jul 17 12:31:16 2017 +0000
+++ b/lang/php71/distinfo       Mon Jul 17 14:10:08 2017 +0000
@@ -1,4 +1,4 @@
-$NetBSD: distinfo,v 1.23 2017/07/07 03:12:22 taca Exp $
+$NetBSD: distinfo,v 1.24 2017/07/17 14:10:08 manu Exp $
 
 SHA1 (php-7.1.7.tar.bz2) = 1d7112102e79b052ebc47e3fd90ad24ddcfb8394
 RMD160 (php-7.1.7.tar.bz2) = bcba338427733569b3be8ed27c5dba2afc3fca80
@@ -17,6 +17,7 @@
 SHA1 (patch-ext_recode_recode.c) = a97a1815d6a41410f68c289debbb9396128a2159
 SHA1 (patch-ext_sqlite3_libsqlite_sqlite3.c) = 8a529a1b3f7c97731f2e719d006f67c3a7259bb5
 SHA1 (patch-ext_standard_basic__functions.c) = f97a2748c7b15fbd9a2d3c21e56079088cc05d56
+SHA1 (patch-ext_standard_uniqid.c) = feefb8c6e601dee690d2ae99443e285136ef7224
 SHA1 (patch-ext_xsl_php__xsl.h) = a9877bff7bacc77926a4541a0ac171c00ad1a627
 SHA1 (patch-makedist) = 2ac0e0391c031c4fcf4993e2269cde4c6bfddfd5
 SHA1 (patch-php.ini-development) = dd65962000ec06439fae3c9bf252fa46be4e33fd
diff -r 4912c512ec5a -r a0d5488bc66e lang/php71/patches/patch-ext_standard_uniqid.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lang/php71/patches/patch-ext_standard_uniqid.c    Mon Jul 17 14:10:08 2017 +0000
@@ -0,0 +1,62 @@
+$NetBSD: patch-ext_standard_uniqid.c,v 1.1 2017/07/17 14:10:08 manu Exp $
+
+PHP uniqid() relies on microsecond-precise system clock to produce an
+unique identifier. In order to avoid  using the same value, it first
+calls usleep(1) to wait for the next microsecond. 
+
+Unfortunately, usleep() specification says "The suspension time may be 
+longer than requested due to the scheduling of other activity by the 
+system." Indeed, the pause may as as long as an entire execution slice, 
+causing a uniqid() call to last more than 10 ms.
+
+This is fixed by replacing the usleep() call by time polling using
+gettimeofday() until the microscecond change. Since the getttimeoday()
+system call lasts around a microsecond, only a small time is wasted
+calling  multiple gettimeofday. On the benefit side, uniqid() performance
+in increased 10000 fold without changing its behavior.
+
+Submitted upstream as https://bugs.php.net/bug.php?id=74851
+
+--- ext/standard/uniqid.c.orig 2017-06-07 10:09:31.000000000 +0200
++++ ext/standard/uniqid.c      2017-07-08 08:24:24.000000000 +0200
+@@ -52,25 +52,31 @@
+       zend_string *uniqid;
+       int sec, usec;
+       size_t prefix_len = 0;
+       struct timeval tv;
++      static struct timeval prev_tv = { 0, 0 };
+ 
+       if (zend_parse_parameters(ZEND_NUM_ARGS(), "|sb", &prefix, &prefix_len,
+                                                         &more_entropy)) {
+               return;
+       }
+ 
+-#if HAVE_USLEEP && !defined(PHP_WIN32)
+       if (!more_entropy) {
+-#if defined(__CYGWIN__)
+-              php_error_docref(NULL, E_WARNING, "You must use 'more entropy' under CYGWIN");
+-              RETURN_FALSE;
+-#else
+-              usleep(1);
+-#endif
++              /* This implementation needs current microsecond to change,
++               * hence we poll time until it does. This is much faster than
++               * calling usleep(1) which may cause the kernel to schedule
++               * another process, causing a pause of around 10ms. 
++               */
++              do {
++                      (void)gettimeofday((struct timeval *) &tv,
++                                         (struct timezone *) NULL);
++              } while (tv.tv_sec == prev_tv.tv_sec && 
++                       tv.tv_usec == prev_tv.tv_usec); 
++
++              prev_tv.tv_sec = tv.tv_sec;
++              prev_tv.tv_usec = tv.tv_usec;
+       }
+-#endif
+-      gettimeofday((struct timeval *) &tv, (struct timezone *) NULL);
++
+       sec = (int) tv.tv_sec;
+       usec = (int) (tv.tv_usec % 0x100000);
+ 
+       /* The max value usec can have is 0xF423F, so we use only five hex