After scalability problems had been detected when using the sysV ipcs, I
have proposed to use an RCU based implementation of the IDR api instead
(see thread http://lkml.org/lkml/2008/4/11/212).

Resending the patch series after
 . integrating Paul's remarks
 . fixing a bug I had introduced
 . porting it to 2.6.25-mm1.

Reviewers are still welcome!

Patch 1 can be taken alone: it fixes a problem in the existing IDR API.

Patches should be applied on linux-2.6.25-mm1, in the following order:

[ PATCH 01/10 ] : idr_minor_fix.patch
[ PATCH 02/10 ] : ridr_structure.patch
[ PATCH 03/10 ] : ridr_pre_get.patch
[ PATCH 04/10 ] : ridr_init.patch
[ PATCH 05/10 ] : ridr_get_new_above.patch
[ PATCH 06/10 ] : ridr_get_new.patch
[ PATCH 07/10 ] : ridr_find.patch
[ PATCH 08/10 ] : ridr_remove.patch
[ PATCH 09/10 ] : ipc_use_ridr.patch
[ PATCH 10/10 ] : remove_ipc_lock_down.patch

Regards,
Nadia


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On Tue, 29 Apr 2008 16:33:04 +0200

hm, you've been busy.

As all this work is entirely for performance reasons, the changelog should
have (lots of) performance testing results!  Please.


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Here are the results I've got  for the pmsg test sent by Manfred:

for i in 1 2 3 4 5 6 7 8;do ./pmsg $i 5;done > output.25_mm1.ref.8
for i in 1 2 3 4 5 6 7 8;do ./pmsg $i 5;done > output.25_mm1.patch.8


                 2.6.25-mm1 (ref)   2.6.25-mm1(patched)

Total (1 cpu):   876000             985496
Total (2 cpus): 1549592            1740591
Total (3 cpus): 1694370            2327468
Total (4 cpus):  404553            2465787
Total (5 cpus):  391283            3215676
Total (6 cpus):  263249            3849121
Total (7 cpus):  191742            4209866
Total (8 cpus):  141722            4255585



Full output files attached.

Will send the rest tomorrow.

Regards
Nadia

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Looks encouraging.  A comparison with 2.6.22 (or whichever kernel it was

Nobody reads the raw data, sorry.  And it is inefficient to have everyone
independently pore over the raw data extracting the (same) actual
information.

Please condense the result of your performance testing into a
preferably-less-than-one-page summary and include (and maintain) that within
the patch changelog.

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