ID: 49383 Updated by: ras...@php.net Reported By: olga at metacafe dot com -Status: Open +Status: Bogus Bug Type: Performance problem Operating System: Red Hat 3.4.6-10 PHP Version: 5.3, 6 New Comment:
You suppose it is because of fstat? I seriously doubt that. fstat is really fast because it doesn't need to touch the disk at all. It simply grabs the stat struct from an already open file descriptor. If you can show me some profiling numbers where fstat is anywhere on the radar, I'll take a look, but I am highly suspicious that fstat would have anything to do with any performance issues. Disk-touching stats like lstat are the ones you need to worry about. Previous Comments: ------------------------------------------------------------------------ [2009-09-01 14:48:03] olga at metacafe dot com Any PHP code does it. The code: <?php echo "Hello!"; ?> The strace: open("[path]/test.php", O_RDONLY) = 16 fstat(16, {st_mode=S_IFREG|0644, st_size=82, ...}) = 0 fstat(16, {st_mode=S_IFREG|0644, st_size=82, ...}) = 0 fstat(16, {st_mode=S_IFREG|0644, st_size=82, ...}) = 0 mmap(NULL, 82, PROT_READ, MAP_SHARED, 16, 0) = 0x2a9a8b4000 munmap(0x2a9a8b4000, 82) = 0 close(16) = 0 ------------------------------------------------------------------------ [2009-08-31 11:48:20] j...@php.net Thank you for this bug report. To properly diagnose the problem, we need a short but complete example script to be able to reproduce this bug ourselves. A proper reproducing script starts with <?php and ends with ?>, is max. 10-20 lines long and does not require any external resources such as databases, etc. If the script requires a database to demonstrate the issue, please make sure it creates all necessary tables, stored procedures etc. Please avoid embedding huge scripts into the report. ------------------------------------------------------------------------ [2009-08-31 08:32:54] olga at metacafe dot com Used the snapshot, nothing changed. Fstat() remains high. ------------------------------------------------------------------------ [2009-08-29 00:26:57] j...@php.net Please try using this snapshot: http://snaps.php.net/php5.3-latest.tar.gz For Windows: http://windows.php.net/snapshots/ ------------------------------------------------------------------------ [2009-08-27 07:54:43] olga at metacafe dot com Description: ------------ Hi, We recently upgraded our web servers with PHP 5.3 and found out that there are lots of empty fstat system calls. fstat is called 3 times on each file open. This does not happen on PHP 5.2.9. PHP 5.2.9 shows better results in benchmarking vs. 5.3.0, and I suppose it's because of the fstat. We're running Red Hat 3.4.6, Apache 2.0.59, PHP 5.3.0 Reproduce code: --------------- Any code that loads PHP file. Expected result: ---------------- Strace summary from 5.2.9 % time seconds usecs/call calls errors syscall 44.65 34.487815 159 217129 26 lstat 8.73 6.743625 170 39745 145 stat 8.23 6.355874 170 37466 18 open 8.21 6.345542 167 38091 close 7.99 6.170706 165 37410 fstat Strace summary from 5.3.0 % time seconds usecs/call calls errors syscall 22.64 28.292541 301 93945 fstat 18.39 22.979631 312 73713 110 lstat 9.23 11.529433 311 37131 munmap 9.14 11.417404 306 37277 mmap 8.52 10.643572 306 34755 149 stat Actual result: -------------- Strace result. I replaced full path by [path] open("[path]/Flash.php", O_RDONLY) = 21 fstat(21, {st_mode=S_IFREG|0777, st_size=23902, ...}) = 0 fstat(21, {st_mode=S_IFREG|0777, st_size=23902, ...}) = 0 fstat(21, {st_mode=S_IFREG|0777, st_size=23902, ...}) = 0 mmap(NULL, 23902, PROT_READ, MAP_SHARED, 21, 0) = 0x2a971a2000 stat("[path]/Flash.php", {st_mode=S_IFREG|0777, st_size=23902, ...}) = 0 munmap(0x2a971a2000, 23902) = 0 close(21) = 0 lstat("[path]/VTalkNotification.php", {st_mode=S_IFREG|0777, st_size=778, ...}) = 0 lstat("[path]/VTalkNotification.php", {st_mode=S_IFREG|0777, st_size=778, ...}) = 0 open("[path]/VTalkNotification.php", O_RDONLY) = 21 fstat(21, {st_mode=S_IFREG|0777, st_size=778, ...}) = 0 fstat(21, {st_mode=S_IFREG|0777, st_size=778, ...}) = 0 fstat(21, {st_mode=S_IFREG|0777, st_size=778, ...}) = 0 mmap(NULL, 778, PROT_READ, MAP_SHARED, 21, 0) = 0x2a971a2000 stat("[path]/VTalkNotification.php", {st_mode=S_IFREG|0777, st_size=778, ...}) = 0 munmap(0x2a971a2000, 778) = 0 close(21) = 0 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=49383&edit=1