Re: Oprofile report doesnot show symbol information of sctp module

[Maynard J. <may...@us...>]

On 08/26/2010 1:46 AM, Santosh Sahoo wrote:
>
>
> Hi ,
>
> We have a C++ application that uses lksctp for transmission and reception of
> SCTP message. Our application does not report consistent message transfer rate
> (Tx and Rx) when multiple (two or three) instances of the same application are
> being run. I mean, the data rate is approximately 8k messages per second using a
> single application, however total messages per sec. get dropped to 18k when
> three instances of the same application are run. We have symmetric
> multi-processor (SMP) system with 4 CPUs (2GHz each).
>
> To identify the performance bottleneck, we did profiling the system with
> OProfile (version 0.8.1) with following settings
>
> ~/.oprofile/daemonrc
>
> CHOSEN_EVENTS[0]=CPU_CLK_UNHALTED:100000:0:1:1
>
> NR_CHOSEN=1
>
> SEPARATE_LIB=0
>
> SEPARATE_KERNEL=1
>
> SEPARATE_THREAD=0
>
> SEPARATE_CPU=0
>
> VMLINUX=/usr/lib/debug/lib/modules/2.6.9-55.ELsmp/vmlinux
>
> IMAGE_FILTER=
>
> CPU_BUF_SIZE=0
>
> CALLGRAPH=0
>
> The opreport –l obtained from the profiled data shows the SCTP module has been
> sampled maximum no of times but it doesn’t display the symbol information of
> sctp. The first 5 samples from opreport are as below.

Use "opreport -l --image-path=/lib/modules/`uname -r` ".  The image-path option 
tells oprofile where to find your kernel modules so it can look into them to do 
address-to-symbol resolution.

BTW, oprofile 0.8.1 is ancient.  If you run into *any* problems using it, you 
should try building/installing the latest release (0.9.6).

-Maynard
>
> CPU: Core Solo / Duo, speed 1995.21 MHz (estimated)
>
> Counted CPU_CLK_UNHALTED events (Unhalted clock cycles) with a unit mask of 0x00
> (Unhalted core cycles) count 100000
>
> samples % app name symbol name
>
> 30498 9.3073 sctp (no symbols)
>
> 14241 4.3460 vmlinux sock_poll
>
> 13684 4.1761 vmlinux fget
>
> 10322 3.1500 vmlinux get_offset_pmtmr
>
> 9210 2.8107 vmlinux _spin_lock_irqsave
>
> System configurations:
>
> Redhat Enterprise Linux 2.6.9-55ELsmp.
>
> gcc version 3.4.6 20060404 (Red Hat 3.4.6-8)
>
> oprofile version 0.8.1
>
> RPMs installed:
>
> gcc-debuginfo-3.4.6-8
>
> kernel-debuginfo-2.6.9-55.EL
>
> lksctp-tools-1.0.8-1
>
> lksctp-tools-devel-1.0.8-1
>
> Please note that our application is also built with debug information. Note
> that, we also build the kernel source tree locally and installed newly build
> modules, bzImage and debuginfo rpm in the system. But still we are unable to get
> the symbol information of sctp module.
>
> Can anyone help us to provide the steps (that we may have missed) to capture the
> symbol information of sctp module? Thanking you in advance for your help and
> comments.
>
> Regards,
>
> Santosh
>
>
>
>
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