====== Request for Comments: TSRMLS_FETCH() reduction ======
  * Version: 1.0
  * Date: 2010-09-09
  * Author: Felipe Pena <felipe@php.net>, Pierre Alain Joye <pajoye@php.net>
  * Status: Under implementation

===== Introduction =====

The purpose of RFC is to show a way to reduce several function call by avoiding useless TSRMLS_FETCH() usage on ZTS. Adding TSRMLS_CC to the memory allocation macros/function, hash api, zend_llist and streams.

===== Changes ======

See below some macros/functions will be added by the patch.

^ Current function/macro ^ New function/macro ^
| emalloc          | emalloc2    |
| ecalloc          | ecalloc2    |
| pemalloc         | pemalloc2   |
| erealloc         | erealloc2   |
| efree            | efree2      |
| estrdup          | estrdup2    |
| estrndup         | estrndup2   |

===== Profiler =====

Using cachegrind (//valgrind --tool=cachegrind --cachegrind-out-file=profile sapi/cli/php Zend/bench.php//) to see the improvement, we can see the follow differences:

^ Function ^ Ir (Patched) ^ Ir (Current) ^
| pthread_getspecific | 498,129,021 | 1,269,764,085 |
| ts_resource_ex | 394,353,075 | 1,005,230,834 |
| efree | 459,940,754 | 840,217,602 |

^ Ir Total (Patched) ^ Ir Total (Current) ^
| 42,537,064,394 | 44,080,331,320 |

// Ir - Instruction read //

===== Benchmark =====

==== Zend/bench.php ====

^ Zend/bench.php    ^ Patched ^ Current ^
| simple            | 0.487 | 0.562 |
| simplecall        | 1.697 | 1.971 |
| simpleucall       | 1.827 | 2.152 |
| simpleudcall      | 1.879 | 2.198 |
| mandel            | 1.950 | 2.286 |
| mandel2           | 3.001 | 3.719 |
| ackermann(7)      | 1.426 | 1.874 |
| ary(50000)        | 0.260 | 0.256 |
| ary2(50000)       | 0.201 | 0.239 |
| ary3(2000)        | 1.506 | 1.758 |
| fibo(30)          | 5.065 | 5.618 |
| hash1(50000)      | 0.335 | 0.364 |
| hash2(500)        | 0.295 | 0.369 |
| heapsort(20000)   | 0.791 | 0.925 |
| matrix(20)        | 0.697 | 0.765 |
| nestedloop(12)    | 0.921 | 0.976 |
| sieve(30)         | 1.077 | 1.146 |
| strcat(200000)    | 0.130 | 0.148 |
| Total             | 23.547 | 27.328 |

==== Zend/microbench.php ====

**Patched**
<code>
empty_loop         0.810
func()             3.588    2.778
undef_func()       3.775    2.965
int_func()         3.651    2.841
$x = self::$x      2.108    1.297
self::$x = 0       1.878    1.067
isset(self::$x)    1.676    0.865
empty(self::$x)    1.754    0.944
$x = Foo::$x       1.830    1.019
Foo::$x = 0        1.746    0.936
isset(Foo::$x)     1.543    0.733
empty(Foo::$x)     1.673    0.863
self::f()          3.764    2.954
Foo::f()           3.581    2.770
$x = $this->x      2.161    1.351
$this->x = 0       3.719    2.909
$this->x += 2      1.863    1.053
++$this->x         1.547    0.737
--$this->x         1.665    0.855
$this->x++         1.524    0.714
$this->x--         1.532    0.722
isset($this->x)    1.726    0.915
empty($this->x)    1.891    1.081
$this->f()         4.151    3.341
$x = Foo::TEST     1.628    0.818
new Foo()         10.194    9.384
$x = TEST          1.327    0.517
$x = $_GET         2.167    1.357
$x = $GLOBALS['v'] 2.897    2.086
$x = $hash['v']    2.034    1.224
$x = $str[0]       5.311    4.500
------------------------
Total             80.712
</code>

**Current (trunk)**
<code>
empty_loop         0.798
func()             3.634    2.836
undef_func()       3.633    2.836
int_func()         3.896    3.099
$x = self::$x      2.129    1.332
self::$x = 0       1.945    1.148
isset(self::$x)    1.755    0.958
empty(self::$x)    1.660    0.863
$x = Foo::$x       1.986    1.189
Foo::$x = 0        1.769    0.971
isset(Foo::$x)     1.556    0.759
empty(Foo::$x)     1.750    0.953
self::f()          4.268    3.470
Foo::f()           3.874    3.077
$x = $this->x      2.260    1.462
$this->x = 0       4.357    3.559
$this->x += 2      2.006    1.208
++$this->x         1.658    0.860
--$this->x         1.643    0.846
$this->x++         1.804    1.007
$this->x--         1.818    1.021
isset($this->x)    1.832    1.035
empty($this->x)    2.050    1.253
$this->f()         4.537    3.739
$x = Foo::TEST     1.804    1.006
new Foo()         10.702    9.904
$x = TEST          1.558    0.760
$x = $_GET         2.274    1.476
$x = $GLOBALS['v'] 3.105    2.307
$x = $hash['v']    1.939    1.141
$x = $str[0]       5.371    4.573
------------------------
Total             85.372
</code>

===== Patch =====

http://felipe.ath.cx/diff/tsrmls-fetch-reduction.diff

===== Changelog =====

2010-09-09: Started.