This replaces the GUI element used for execution timeout handling
on Windows. Instead a timer queue technique is used, which is indeed
a thread pool. A timer queue timer is a lightweight object handled
but that thread pool and the timer thread spends most of the time
sleeping and waiting for an alert.
Please note also that this introduces neither binary nor source
breach. The custom timeout thread functions are deleted, however
they was not exported throug DLL, so couldn't be used by any
external code. As well they couldn't be used anywhere in the core
except in executor api, because those custom timeout thread
functions they used to operate on static variables which would
be overwritten (and that would blow).
So instead a relatively modern technique is used for the timeout
handling. It's still not perfect because the executor still has to
check EX(timed_out). This can be a topic for an improvement in
master. But brobably can be tricky as currently it seems to be not
possible to signal an individual thread. Also note another issue
that static variables aren't thread safe, but the current timer
implementation is.
the main idea - the smaller the zend_op structure, the lees memory traffic is required to load VM instructions during execution. The patch reduces the size of each opcode from 48 to 32 bytes (saves 16 bytes for each opcode, and applications use thousands of opoceds). This reduced the number of CPU cache misses by 12% and improved performance of real-life apps by 1-2%.
The patch affects how constants and jump targets are represented in VM during execution. Previously they were implemented as absolute 64-bit pointers. Now they are relative 32-bit offsets.
In run-time constant now should be accessed as:
RT_CONSTANT(op_array, opine->op1) instead of opline->op1.zv
EX_CONSTANT(opline->op1) instead of opline->op1.zv
Jump targets:
OP_JMP_ADDR(opline, opline->op2) instead of opline->op2.jmp_addr
The patch doesn't change zend_op representation for 32-bit systems. They still use absolute addresses. The compile-time representation is also kept the same.
Splited the most expensive part of inline i_zend_is_true() into a separate zend_object_is_true().
Replaced zendi_convert_to_long() with cals to zend_is_true().
As zend_fcall_info_args_clear() calls zval_ptr_dtor() we also have
to increase the refcount of refcounted zvals added as params,
like it is already done in zend_fcall_info_args_ex().
With that, also fixed bug #68297 (Application Popup provides too few
information) as a better error message is provided to the event log.
In the second case, the condition for display_startup_error was removed. The
condition was added as a fix for bug #30760 which was preventing the
MessageBox to appear. When display_startup_error=on, the error will be seen
on the console. But when running under a webserver it'll probably get lost,
so we need to log it other way into the event log (would be done automatically
when message box was used, but that would eventually cause issues of blocked
execution).
Generally speaking - any MessageBox or other graphical element is a potential
issue and that was repeatedly reported. Graphical elements shouldn't be used
in the core. Even being a rare one it can cause a bad situation where the
server is blocked. Yet some places have to cleaned up.
