Oh, probably this is just the biggest prime number that fits into a signed 16-bit number :)
On Mon, Jan 17, 2022 at 10:49 AM Su, Tao <tao...@intel.com> wrote: > Thanks Dmitry for the information. > > With a few debug sessions, I found that 32531 is working well > for any thresholds, and is also a big prime number :-). > > > -----Original Message----- > From: Dmitry Stogov <dmitrysto...@gmail.com> > Sent: Monday, January 17, 2022 1:37 PM > To: Su, Tao <tao...@intel.com> > Cc: PHP internals <internals@lists.php.net> > Subject: Re: [PHP-DEV] Reason for ZEND_JIT_COUNTER_INIT set to 32531? > > This it's my choice. > This number is common for all JIT counters (hot_loop, hot_func, > hot_return). > It's value was selected to provide the best precision when different > counters have different thresholds. > Unfortunately, I can't remember the exact equations or logic I used at > that time. > > Thanks. Dmitry. > > On Thu, Jan 13, 2022 at 1:01 PM Su, Tao <tao...@intel.com> wrote: > > > Hi Internal, > > I am not sure this is a correct mail list for asking source code > > related question. > > If not, I am sorry. Appreciate you guys' help. > > > > I am reading PHP8 JIT related source code and found that zend_jit.h > > has a magic definition ZEND_JIT_COUNTER_INIT as 32531 which I do not > > quite understand how this number was chosen and why? > > Anybody can provide some historic information? > > #define ZEND_JIT_COUNTER_INIT 32531 > > > > A code example using this definition (looks like the 2nd parameter > > computes into a fixed number if hot_func is set by php.ini) > > ZEND_OPCODE_TAIL_CALL_EX(zend_jit_trace_counter_helper, > > ((ZEND_JIT_COUNTER_INIT + JIT_G(hot_func) - 1) / > > JIT_G(hot_func))); > > > > > > ======================================= > > Tony Su (Su, Tao) > > make a 'lazy' programmer diligently with efficiency > > > > >
