lkml.org 
[lkml]   [2007]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC][PATCH 1/6] Storing ipcs into IDRs
Nadia Derbey wrote:
> Andi Kleen wrote:
>
>> Nadia.Derbey@bull.net writes:
>>
>>
>>> This patch introduces ipcs storage into IDRs. The main changes are:
>>> . This ipc_ids structure is changed: the entries array is changed
>>> into a
>>> root idr structure.
>>> . The grow_ary() routine is removed: it is not needed anymore when
>>> adding
>>> an ipc structure, since we are now using the IDR facility.
>>> . The ipc_rmid() routine interface is changed:
>>> . there is no need for this routine to return the pointer
>>> passed in as
>>> argument: it is now declared as a void
>>> . since the id is now part of the kern_ipc_perm structure, no
>>> need to
>>> have it as an argument to the routine
>>>
>>
>>
>> Thanks for doing this work. It was long overdue.
>>
>> Do you have any data how this changes memory consumption with many
>> objects?
>> -Andi
>>
>
> Andi,
>
> Here are the results I got when creating 32768 (IPCMNI) msg queues with
> the patched kernel:
>
> http://akt.sourceforge.net/results/2.6.23-rc2-idr/msg11/output.new
>
> It's the output from msg11.c. This script does what follows:
> . gets sysinfo(2) results
> . captures /proc/meminfo
> . captures /proc/slabinfo
> . creates XX msg queues (XX given as parameter)
> . captures /proc/meminfo
> . captures /proc/slabinfo
> . gets sysinfo results
> . outputs all the results
> . removes the created ipcs
>
> sysinfo results: a BEFORE and an AFTER column are output where necessary.
> BEFORE means "before creating the objects"
> AFTER means "after the objects have been created"
>
> meminfo results: the BEFORE and AFTER files are pasted
>
> slabinfo results: only the differences between the BEFORE and the AFTER
> are output.
>
>
> Here are also the sizes for the ref and the patched kernel:
>
> size linux-2.6.23-rc2.ref/vmlinux linux-2.6.23-rc2/vmlinux
> text data bss dec hex filename
> 4432697 496450 602112 5531259 54667b linux-2.6.23-rc2.ref/vmlinux
> 4430747 496450 602112 5529309 545edd linux-2.6.23-rc2/vmlinux
>
>
>
> The http://akt.sourceforge.net/results/2.6.23-rc2-idr/msg11 directory is
> structured as follows:
>
> msg11.c: the script I used to generate the results
> output.ref: the output from msg11 with the ref kernel
> output.new: the output from msg11 with the patched kernel
> size: the output from the size command
> ref: directory with the results files for the ref kernel
> new: directory with the results files for the patched kernel
> In these 2 directories:
> *_mem_*before: /proc/meminfo before creating the msg queues
> *_mem_*after: /proc/meminfo after creating the msg queues
> *_slab_*before: /proc/slabinfo before creating the msg queues
> *_slab_*after: /proc/slabinfo after creating the msg queues
>

Andi,

Here is an annalysis of the results I sent you yesterday (I guess you
don't have enoguh time to look at everything):

ref code:

1) since /proc/sys/kernel/msgmni has been set to 32768, vmalloc(0x20014)
is called to allocate the entries[] array (see grow_ary() -->
ipc_rcu_alloc()).

==>

Before msg queues allocation: VmallocUsed = 2860 kB
After msg queues allocation: VmallocUsed = 2996 KB

Once allocated this array is never freed.

Unfortunately, in the result I sent you yesterday, you can't see the
evolution since it was not the 1st time I was running the test, so the
vmalloc() has not been called.


2) Since 32768 msg queues have been created and a msg_queue structure <
PAGE_SIZE, kmalloc(0x6C) is called 32768 times

==> size-128 in slabinfo: (I slighty simplified the output to make it
fit in the mail):

objs slabs
# name <active> <num> <size> : <active> <num>
before : size-128 1070 1320 128 : 44 44
after : size-128 33840 33840 128 : 1128 1128


patched code:
1) since 32768 msg queues are created, idr_pre_get() is called 32768 times
==> idr_layer_cache in slabinfo:

objs slabs
# name <active> <num> <size> : <active> <num>
before : idr_layer_cache 112 116 136 : 4 4
after : idr_layer_cache 1189 1189 136 : 41 41

2) This point remains unchanged compared to the ref code.



Regards,
Nadia
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-09-07 17:15    [W:0.052 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site