Thanks for the review! Pushed to master with the proposed changes. See a small
comment below, though.
Jarno
On Mar 25, 2014, at 5:16 PM, Ben Pfaff <b...@nicira.com> wrote:
> On Mon, Mar 24, 2014 at 10:59:06AM -0700, Jarno Rajahalme wrote:
>> This patch shrinks the struct ofpbuf from 104 to 48 bytes on 64-bit
>> systems, or from 52 to 36 bytes on 32-bit systems (counting in the
>> 'l7' removal by the previous patch). This may help contribute to
>> cache efficiency, and will speed up initializing, copying and
>> manipulating ofpbufs. This is potentially important for the DPDK
>> datapath, but the rest of the code base may also see a little benefit.
>>
>> Changes are:
>>
>> - Remove 'l7' pointer (previous patch).
>> - Use offsets instead of layer pointers for l2_5, l3, and l4 using
>> 'l2' as basis. Usually 'data' is the same as 'l2', but this is not
>> always the case (e.g., when parsing or constructing a packet), so it
>> can not be easily used as the offset basis. Also, packet parsing is
>> faster if we do not need to maintain the offsets each time we pull
>> data from the ofpbuf.
>> - Use uint32_t for 'allocated' and 'size', as 2^32 is enough even for
>> largest possible messages/packets.
>> - Use packed enum for 'source'.
>> - Rearrange to avoid unnecessary padding.
>> - Remove 'private_p', which was used only in two cases, both of which
>> had the invariant ('l2' == 'data'), so we can temporarily use 'l2'
>> as a private pointer.
>>
>> Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
>
> ofpbuf_resize_l2() and ofpbuf_resize_l2_5() look kind of big to me for
> inlining.
>
I moved them to ofpbuf.c. However, looks can be deceiving, as the
'increment’ is always a compile-time constant, so only one of the ofpbuf
calls will be compiled in for an inlined function.
> ofpbuf_resize_l2() looks rather redundant with ofpbuf_resize_l2_5().
> I think it could be written as:
>
> static inline void * ofpbuf_resize_l2(struct ofpbuf *b, int increment)
> {
> ofpbuf_resize_l2_5(b, increment);
> OFPBUF_ADJUST_LAYER_OFFSET(b, l2_5, increment);
> return b->l2;
> }
>
Changed.
> I don't think OFPBUF_ADJUST_LAYER_OFFSET() really needs to be a macro,
> e.g.:
> static inline void
> ofpbuf_adjust_layer_offset(uint16_t *offset, int increment)
> {
> if (*offset != UINT16_MAX) {
> *offset += increment;
> }
> }
>
Changed, and moved to the C file with the functions.
> Acked-by: Ben Pfaff <b...@nicira.com>
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