Patch for optimize context switch

FASSINO Jean-Philippe jeanphilippe.fassino at cnet.francetelecom.fr
Tue Feb 22 22:23:46 EST 2000


FASSINO Jean-Philippe wrote:

> Paul Mackerras wrote:
>
> > Interesting.  How much does it reduce the context switch time?  Did you
> > run lmbench or something to see if it makes it go faster?

I have got result of lmbench for Context switching (initlevel 1).
I'm running 5 bench with and without patch on a PBG3/400.
Result is in attach. The average is :

Context switching - times in microseconds - smaller is better
-------------------------------------------------------------
Host                 OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K
                        ctxsw  ctxsw  ctxsw ctxsw  ctxsw   ctxsw   ctxsw
--------- ------------- ----- ------ ------ ------ ------ ------- -------

With patch. ======
ppc-linux Linux 2.2.15p  0.6      8     91    26    117      28     239

Without patch ======
ppc-linux Linux 2.2.15p    1      7    102    26    121      28     240


What do you think about this result ???
I'm thinking to say something it is necessary to do many bench run !
Here, performance vary too much between two run to really say something.

Jean-Philippe

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Jean-Philippe FASSINO  Tel :  04 76 76 45 52
CNET : DTL/ASR         mailto:jeanphilippe.fassino at cnet.francetelecom.fr
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-------------- next part --------------
Context switching - times in microseconds - smaller is better
-------------------------------------------------------------
Host                 OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K
                        ctxsw  ctxsw  ctxsw ctxsw  ctxsw   ctxsw   ctxsw
--------- ------------- ----- ------ ------ ------ ------ ------- -------
ppc-linux Linux 2.2.15p    1      7     90    26    107      31     222
ppc-linux Linux 2.2.15p    1      7     91    26    110      29     257
ppc-linux Linux 2.2.15p    1      7     90    25    112      26     233
ppc-linux Linux 2.2.15p    1      7     92    25    126      27     243
ppc-linux Linux 2.2.15p    1      7    147    26    150      27     245
ppc-linux Linux 2.2.15p    0      7     92    25    136      28     270
ppc-linux Linux 2.2.15p    1      8     90    27    103      27     211
ppc-linux Linux 2.2.15p    0      9     90    30    112      32     228
ppc-linux Linux 2.2.15p    1      7     91    25    130      29     277
ppc-linux Linux 2.2.15p    1      7     90    25    105      26     211


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