[Bugme-new] [Bug 12369] New: Performace drop from 2.6.10 to 2.6.18
bugme-daemon at bugzilla.kernel.org
bugme-daemon at bugzilla.kernel.org
Mon Jan 5 22:35:47 PST 2009
http://bugzilla.kernel.org/show_bug.cgi?id=12369
Summary: Performace drop from 2.6.10 to 2.6.18
Product: Other
Version: 2.5
KernelVersion: 2.6.18
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Other
AssignedTo: other_other at kernel-bugs.osdl.org
ReportedBy: cli4 at alcatel-lucent.com
Latest working kernel version: 2.6.10
Earliest failing kernel version: 2.6.18
Distribution: MontaVista CGE4/CGE5
Hardware Environment: PowerPC 750
Software Environment: MontaVista CGE4/CGE5
Problem Description:
We are working an embeded Linux using MontaVista CGE. Since we upgraded from
CGE4 (2.6.10) to CGE5 (2.6.18), we found that our applications' performance
drop very much. With writing a small test program, and runing it with strace, I
found the main performance difference is on futex system. It seems futex on
CGE5 is much heavier than on CGE4.
strace data on CGE4 looks like this:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
39.26 0.060724 222 274 write
38.64 0.059762 2 27246 time
19.51 0.030168 1 27244 nanosleep
1.29 0.002002 501 4 1 futex
0.64 0.000995 995 1 execve
0.37 0.000579 2 274 gettimeofday
------ ----------- ----------- --------- --------- ----------------
100.00 0.154657 55102 12 total
While on CGE5 is:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
69.14 0.347917 69583 5 1 futex
23.53 0.118406 4 29890 nanosleep
6.62 0.033335 1 29892 time
0.52 0.002606 9 300 write
0.07 0.000357 1 300 gettimeofday
0.05 0.000239 239 1 execve
------ ----------- ----------- --------- --------- ----------------
100.00 0.503226 60446 10 total
Steps to reproduce:
1. Write a simple C program that just looply certain time to do nanosleep 5ms.
2. Build the program to executable named tnano.
2. Use this command "strace -Ffctrr -o nosleep.trace ./tnano" to it on both
2.6.10 and 2.6.18, and cat nosleep.trace to see data.
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