From:             jost_boekemeier at users dot sf dot net
Operating system: Irrelevant
PHP version:      5.3.0alpha2
PHP Bug Type:     Performance problem
Bug description:  FastCGI is incredibly slow due to TCP ack delay

Description:
------------
The PHP side of a socket-based FastCGI communication is unbuffered since
PHP 5.1.4 (maybe earlier). 

write/write/read cycles have a huge performance impact, on the latest
Linux kernel the FastCGI SAPI is actually slower than executing a CGI for
each request!

The actual problem is caused by the two unbuffered write() operations,
which run into a delayed ack and therefore cause a latency of 40000us on
FC10 and 500ms(!) on FreeBSD.

As an immediate fix I suggest to switch on NDELAY for the PHP FastCGI
socket communication. I can provide a patch if you want me to.


Regards,
Jost Bökemeier



Reproduce code:
---------------
-

Expected result:
----------------
-

Actual result:
--------------
-

-- 
Edit bug report at http://bugs.php.net/?id=46723&edit=1
-- 
Try a CVS snapshot (PHP 5.2):        http://bugs.php.net/fix.php?id=46723&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):        http://bugs.php.net/fix.php?id=46723&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):        http://bugs.php.net/fix.php?id=46723&r=trysnapshot60
Fixed in CVS:                        http://bugs.php.net/fix.php?id=46723&r=fixedcvs
Fixed in CVS and need be documented: http://bugs.php.net/fix.php?id=46723&r=needdocs
Fixed in release:                    http://bugs.php.net/fix.php?id=46723&r=alreadyfixed
Need backtrace:                      http://bugs.php.net/fix.php?id=46723&r=needtrace
Need Reproduce Script:               http://bugs.php.net/fix.php?id=46723&r=needscript
Try newer version:                   http://bugs.php.net/fix.php?id=46723&r=oldversion
Not developer issue:                 http://bugs.php.net/fix.php?id=46723&r=support
Expected behavior:                   http://bugs.php.net/fix.php?id=46723&r=notwrong
Not enough info:                     http://bugs.php.net/fix.php?id=46723&r=notenoughinfo
Submitted twice:                     http://bugs.php.net/fix.php?id=46723&r=submittedtwice
register_globals:                    http://bugs.php.net/fix.php?id=46723&r=globals
PHP 4 support discontinued:          http://bugs.php.net/fix.php?id=46723&r=php4
Daylight Savings:                    http://bugs.php.net/fix.php?id=46723&r=dst
IIS Stability:                       http://bugs.php.net/fix.php?id=46723&r=isapi
Install GNU Sed:                     http://bugs.php.net/fix.php?id=46723&r=gnused
Floating point limitations:          http://bugs.php.net/fix.php?id=46723&r=float
No Zend Extensions:                  http://bugs.php.net/fix.php?id=46723&r=nozend
MySQL Configuration Error:           http://bugs.php.net/fix.php?id=46723&r=mysqlcfg