"gRPC uses the HTTP/2 default max size for a data frame of 16kb. A message over 16kb may span multiple data frames, whereas a message below that size may share a data frame with some number of other messages." - grpc.io <https://grpc.io/blog/grpc-on-http2/#footnotes>
"The size of a frame payload is limited by the maximum size that a receiver advertises in the SETTINGS_MAX_FRAME_SIZE setting. This setting can have any value between 2^14 (16,384) and 2^24-1 (16,777,215) octets, inclusive." - RFC 7540 <https://datatracker.ietf.org/doc/html/rfc7540#section-4> I hope it helps. On Monday, August 22, 2022 at 3:53:31 AM UTC-3 al...@identiq.com wrote: > HI again > We tcpdump the traffic. > We see the first 16kb frame is sent from the client to the server, but the > 2nd one is not sent until an ack is returned from the server. > In our case, our msg size is 30KB, and round trip latency is ~220ms. > So because of this, call takes ~440ms instead of ~200ms. > > We set the InitialWindowSize and InitialConnWindowSize to 1MB, on both > server and client - no change. > We checked both unary RPCs and Stream RPCs - the same. > We set the WriteBufferSize and ReadBufferSize to zero (write/read directly > to/from the wire) - 95% latency remained the same, but Avg latency dropped > by 100ms - not sure why it had this effect. > > Again, in all of the conditions above, if we increase to rate of messages > to more then 2 or 3 per second, the latency drops to 450ms > Looking at http2debug=2 logs, we see it seems that in the higher rate the > when latency is low, grpc somehow uses a previous opened stream used by > another RPC to sent the new RPC.... > > Anyone has encountered a similar behaviour. ? > Anyone that understand GRPC implementation (Go lang) can explain why it > behaves this why and if there is a way to make it work better ? > Any help would be very much appreciated > Thanks ! > > > On Wednesday, August 17, 2022 at 4:44:28 PM UTC+3 Alon Kaftan wrote: > >> Also, if we run few dummy (small payload) calls per seconds, in parallel >> to the big payload calls, on the same connection => the latency of the big >> payload calls is reduced to 250ms as well >> Thoughts ? >> >> On Wednesday, August 17, 2022 at 1:46:20 PM UTC+3 Alon Kaftan wrote: >> >>> Hi >>> we have a go grpc client running in US and a go grpc server on APAC. >>> Both on AWS. >>> on the same connection we make Unary calls >>> when the message size is lower than 16KB, roundtrip latency is 250ms >>> when the message size is crossing the 16KKB, round trip latency jumps to >>> 450ms >>> when the message size is crossing the 100KB, round trip latency jumps to >>> 650ms >>> >>> Also, if we increase the rate of the 16KB+ messages from 1/sec to 2/sec >>> or more, the latency drops to 250ms >>> >>> we ruled out load balancers as we connected the client & server pods >>> directly and observed the behaviour remains the same >>> >>> Any ideas where to start with this kind of behaviour ? >>> >>> Thanks! >> >> -- Este e-mail, incluindo seus anexos, é confidencial e de uso exclusivo do destinatário. Seu conteúdo não deve ser revelado a terceiros. Caso você não seja o destinatário, por favor, notifique o remetente e elimine esta mensagem imediatamente. Alertamos que esta mensagem transitou por rede pública de comunicação, estando, portanto, sujeita aos riscos inerentes a essa forma de comunicação. -- You received this message because you are subscribed to the Google Groups "grpc.io" group. To unsubscribe from this group and stop receiving emails from it, send an email to grpc-io+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/49933cbd-6402-422c-a505-816d6ab4dbc6n%40googlegroups.com.
