On Nov 15, 2011, at 12:45, Chuck Remes <[email protected]> wrote:
>
> On Nov 15, 2011, at 2:36 PM, MinRK wrote:
>
>> e.g.
>>
>> struct sequence_id {
>> uint64 number;
>> uchar uuid[16];
>> };
>>
>> Is this all right? Or is there a better way to accomplish this framing?
>>
>> cr
>>
>> I have a general question related to this - what is the relative cost in
>> zeromq of these being separate very-small messages versus one packed
>> message? Has someone done perf tests for this kind of thing?
>
> I haven't tested it, but I assume that reading a multipart message versus a
> single-part message is more time consuming due to 2 factors.
>
> 1. The I/O thread needs to make sure all parts are accounted for before
> atomic delivery.
>
> 2. The #recv has to examine the message frame for the RCVMORE bit.
>
> It's minor work, but as we all know, the fastest code is "no code."
>
> On a related topic, I packed these two details together because they are
> logically related. The unique sequence_id is a combination of sequence_number
> and uuid.
Right - I don't doubt that it's faster in this case, I was just wondering what
the general cost might be, noting that this is presumably always part of a
multipart message, so what is the cost of one extra msg part vs two, on top of
the real content of the message.
For instance, let's say I had two small strings to send that are *not* already
packed together in a struct, under what conditions is it preferable to pack
them into one message, and when is it better to leave them as separate?
MinRK
>
> cr
>
>
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