Re: (RFC): SKB Initialization

[Nivedita Singhvi <niv@us.ibm.com>]

> The patch reduces the numer of cylces by 25%

Er, I'm not getting that from just the numbers you show.

The total ave number of cycles in alloc_skb before is approx 268.

Total number of cycles in alloc_skb after is approx 468. 

So in order to reduce the total ave number of cycles, you
need __kfree_skb to reduce by more than approx 200. (Since
thats where you moved the code to).

So unless we see the total cycles in __kfree_skb, how
do we know? Or what am I missing?

thanks,
Nivedita


You said:



                                CPU 0                 CPU 1
                               ------                 ------
Avg cycles in alloc_skb:        64.05                 203.39
Avg cycles in __kfree_skb:     127.54                 228.95
                               ------                 -------
Total Avg Cycles               191.59                 432.34
                               ------                 -------

# of times alloc_skb called:      235,478            2,060,422
# of times __kfree_skb called:  2,063,276              232,359


Linux 2.5.25+Skbinit Patch:
--------------------------
                              CPU 0                   CPU 1
                              -----                   -----
 Avg cycles in alloc skb:     237.21                  230.91

 # of times alloc_skb called: 1,226,594             1,213,327