Hi Vitali, Instead of using MallocMessageBuilder, have you tried writing a custom subclass of MessageBuilder? It should allow you to customize these things more precisely.
Note that *someone* has to zero out memory before Cap'n Proto can start allocating from it (because Cap'n Proto structures all expect to be zero-initialized anyway, so as an optimizaiton we assume memory is zero'd in advance), but with a custom MessageBuilder you have more control over when it happens. -Kenton On Tue, Aug 20, 2019 at 7:53 AM Vitali Lovich <[email protected]> wrote: > Hi, I'm trying to use cap'n'proto as want efficient in-memory store of > events that adds as little overhead as possible to the act of creating an > event. Where I'm at is that I have per thread buffers that I in-place > allocate a MallocMessageBuilder into a 512 buffer and use the remainder as > scratch. I then defer serialization and destruction onto a background > thread that flushes when there is a listener for the event (no listeners > registered, simply overwrite). This works fine and performs fairly well > (~300ns overhead per event on PC, maybe 1000ns on Android). > > Is there a way I can write a builder to live on the stack and not allocate > it in the ring buffer in this setup? The challenges I ran into are that the > builder zeroes on destruction and mandates that it's initialized with > zeroed memory. > > I'm ok if this adds a restriction on the available arena size which I > don't actually have now (since the builder itself is *very* at 200+ bytes > relative to the events). I would still like to be able to add more data to > the message in the background thread like I do now (eg process name, pid, > etc) that is event-agnostic and can be cheaper to defer filling that in to > the background listener delivery thread. > > -- > You received this message because you are subscribed to the Google Groups > "Cap'n Proto" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/capnproto/CAF8PYMg54h9js%2BRiVhx4TA4DKiLty8iLZiRCUc21iKbmq7fhDQ%40mail.gmail.com > <https://groups.google.com/d/msgid/capnproto/CAF8PYMg54h9js%2BRiVhx4TA4DKiLty8iLZiRCUc21iKbmq7fhDQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/CAJouXQkj28pmsMapya_DihZ2FtdeDKsPFAUTTccGgV4Rz1B4dg%40mail.gmail.com.
