From: Jeff Hostetler Date: Tue, 26 Jul 2022 00:04:50 GMT Subject: Re: [PATCH] fetch-pack: add tracing for negotiation rounds Message-ID: <16998c06-8394-1c8a-06d1-0f7ac4034cf4@jeffhostetler.com> In-Reply-To: On 7/25/22 6:13 PM, Josh Steadmon wrote: > Currently, negotiation for V0/V1/V2 fetch have trace2 regions covering > the entire negotiation process. However, we'd like additional data, such > as timing for each round of negotiation or the number of "haves" in each > round. Additionally, "independent negotiation" (AKA push negotiation) > has no tracing at all. Having this data would allow us to compare the > performance of the various negotation implementations, and to debug > unexpectedly slow fetch & push sessions. > > Fix this by adding per-round trace2 regions for all negotiation > implementations (V0+V1, V2, and independent negotiation), as well as an > overall region for independent negotiation. Add trace2 data logging for > the number of haves and "in vain" objects for each round, and for the > total number of rounds once negotiation completes. Finally, add a few > checks into various tests to verify that the number of rounds is logged > as expected. I've been wanting to add data like this around the negotiation code for a while now. Thanks! > > Signed-off-by: Josh Steadmon > --- > fetch-pack.c | 62 +++++++++++++++++++++++++++++- > t/t5500-fetch-pack.sh | 4 +- > t/t5516-fetch-push.sh | 10 ++++- > t/t5601-clone.sh | 6 ++- > t/t5703-upload-pack-ref-in-want.sh | 6 ++- > 5 files changed, 81 insertions(+), 7 deletions(-) > > diff --git a/fetch-pack.c b/fetch-pack.c > index cb6647d657..01a451e456 100644 > --- a/fetch-pack.c > +++ b/fetch-pack.c > @@ -299,6 +299,7 @@ static int find_common(struct fetch_negotiator *negotiator, > { > int fetching; > int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval; > + int negotiation_round = 0, haves = 0; > const struct object_id *oid; > unsigned in_vain = 0; > int got_continue = 0; > @@ -441,9 +442,19 @@ static int find_common(struct fetch_negotiator *negotiator, > packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid)); > print_verbose(args, "have %s", oid_to_hex(oid)); > in_vain++; > + haves++; > if (flush_at <= ++count) { > int ack; > > + negotiation_round++; > + trace2_region_enter_printf("negotiation_v0_v1", "round", > + the_repository, "round-%d", > + negotiation_round); I'm wondering here if the "round-%d" should have some number of leading zeros so that multiple rounds will sort correctly when you have a bunch of them. I'm also wondering (and this is more of a style thing, so feel free to ignore) if we could just use trace2_region_enter() and make the "label" field be the "round/%04d" and not need the extra args. > + trace2_data_intmax("negotiation_v0_v1", the_repository, > + "haves_added", haves); > + trace2_data_intmax("negotiation_v0_v1", the_repository, > + "in_vain", in_vain); > + haves = 0; Thanks, Jeff