On 7/28/15 10:35 AM, Daniel Borkmann wrote:
On 07/28/2015 07:25 PM, Alexei Starovoitov wrote:
On 7/28/15 8:29 AM, Daniel Borkmann wrote:
+.BR __sync_fetch_and_add()
+can be used on map values in case the map has a value_size of
sizeof(long).
+This is quite often useful for aggregation and accounting of events.
The above is a bit not clear, since both u32 and u64 can be used
as atomic counters.
Right, it's unclear indeed. Perhaps the sizeof(long) should be dropped and
it should say instead "the map has a value_size of 4 or 8 bytes".
that also probably not ideal, since value_size == sizeof(struct elemval)
struct elemval {
u64 packet_rx;
u64 byte_rx;
u32 another_counter;
...
u32 some_useful_field;
};
so the program can keep multiple counters in each map element.
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