Re: SSHFS makes the ROOT launch speed slow?

From: Axel Naumann <Axel.Naumann_at_cern.ch>
Date: Thu, 3 Feb 2011 14:47:05 +0100

Hi,

run strace on root.exe (yes, on Linux). root invokes root.exe, and I believe that's what you are seeing.

Cheers, Axel.

Eduard Avetisyan wrote on 02/02/2011 08:55 PM:
>
>
> On Wed, 2 Feb 2011, Konstantin Olchanski wrote:
>

>> On Wed, Feb 02, 2011 at 08:34:52PM +0100, Eduard Avetisyan wrote:
>>>> On Wed, Feb 02, 2011 at 08:04:12PM +0100, Eduard Avetisyan wrote:
>>>>>
>>>>> The same strace produces ~130 calls in my case, which include but are not 
>>>>> limited to libraries like:
>>>>> open("tls/i686/sse2/libXpm.so.4", O_RDONLY) = -1 ENOENT (No such file or directory)
>>>>
>>>> You have "." in your LD_LIBRARY_PATH. Remove it and those syscalls will go away.
>>>
>>> Good hint! Changing the LD_LIBRARY_PATH from ":$ROOTSYS/lib" to simply 
>>> "$ROOTSYS/lib" (just a colon difference) reduced the startup time from 12s 
>>> to 8s, so by 1/3. Still, it's way slower than a local startup time of 0.1s. 
>>>
>>
>> You are still making the system search for every system library in $ROOTSYS/lib,
>> which I understand is a slow SSHFS filesystem.

>
> Quite the contrary! The $ROOTSYS is local and fast! Only the current
> working directory is on SSHFS!
>
>

>>
>> You can try to put the system library path (/lib, etc) in front of $ROOTSYS/lib,
>> so the loader quickly finds the system libraries and does not touch SSHFS.

> Tried, doesn't change anything (as $ROOTSYS is local anyway). But I found
> that the slow part happens with the following strace signature:
>
> clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb73769b8) = 27680
> waitpid(27680, root [0] [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], WSTOPPED) = 27680
>
> namely, "waitpid(27680," is printed and the rest shows up 8-12 seconds
> later.
>
> Thanks for looking into this!
> Eduard

>>
>> -- 
>> Konstantin Olchanski
>> Data Acquisition Systems: The Bytes Must Flow!
>> Email: olchansk-at-triumf-dot-ca
>> Snail mail: 4004 Wesbrook Mall, TRIUMF, Vancouver, B.C., V6T 2A3, Canada
>>
>>

>
Received on Thu Feb 03 2011 - 14:47:11 CET