From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp55.i.mail.ru (smtp55.i.mail.ru [217.69.128.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 58603452566 for ; Sat, 16 Nov 2019 00:33:21 +0300 (MSK) References: From: Vladislav Shpilevoy Message-ID: <61341332-a57f-1ac1-506b-181cafd38154@tarantool.org> Date: Fri, 15 Nov 2019 22:39:39 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Tarantool-patches] [PATCH v2 1/2] fiber: reset clock stats on fiber.top_enable() List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Serge Petrenko Cc: tarantool-patches@dev.tarantool.org Hi! Thanks for the fixes! See 2 comments below. On 15/11/2019 15:58, Serge Petrenko wrote: > We didn't refresh last remembered clock on fiber.top_enable() > This means that the fiber issuing fiber.top_enable() would get a huge > chunk of cpu time on its first yield. Fix this. > Also reset clock_delta and cpu_miss_count. > > If fiber.top() is issued on the same ev loop iteration as > fiber.top_enable(), clock_delta_last is 0 for both cord and all the > fibers, so report "instant" and "average" stats per last iteration as 0 > instead of NaN. > > Follow-up #2694 > --- > src/lib/core/fiber.c | 21 +++++++++++++++++++++ > src/lua/fiber.c | 12 ++++++++++-- > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/src/lib/core/fiber.c b/src/lib/core/fiber.c > index aebaba7f0..258c094f5 100644 > --- a/src/lib/core/fiber.c > +++ b/src/lib/core/fiber.c > @@ -1203,9 +1203,30 @@ fiber_top_enable() > ev_check_start(cord()->loop, &cord()->check_event); > fiber_top_enabled = true; > > + /* > + * Reset cord and fiber clock stats in order to > + * count from zero even on reenable. > + */ > cord()->clock_acc = 0; > cord()->cpu_miss_count_last = 0; > cord()->clock_delta_last = 0; > + cord()->clock_delta = 0; > + > + struct fiber * fiber; > + rlist_foreach_entry(fiber, &cord()->alive, link) { > + fiber->clock_acc = 0; > + fiber->clock_delta_last = 0; > + fiber->clock_delta = 0; > + fiber->cputime = 0; 1. fiber_reset() should do exactly the same, right? Then why doesn't it nullify clock_delta_last? This mess with numerous time fields, and their reset, looks like a necessity to create a new structure, which would be included into cord and fiber structures. And which would provide methods for cleaning and updating the members. > + } > + > + cord()->sched.clock_acc = 0; > + cord()->sched.clock_delta_last = 0; > + cord()->sched.clock_delta = 0; > + cord()->sched.cputime = 0; > + > + cord()->clock_last = __rdtscp(&cord()->cpu_id_last); > + cord()->cpu_miss_count = 0; > struct timespec ts; > if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts) != 0) { > say_debug("clock_gettime(): failed to get this" > diff --git a/src/lua/fiber.c b/src/lua/fiber.c > index 8b3b22e55..647505643 100644 > --- a/src/lua/fiber.c > +++ b/src/lua/fiber.c > @@ -335,11 +335,19 @@ lbox_fiber_top_entry(struct fiber *f, void *cb_ctx) > lua_newtable(L); > > lua_pushliteral(L, "average"); > - lua_pushnumber(L, f->clock_acc / (double)cord()->clock_acc * 100); > + if (cord()->clock_acc) 2. Sorry for a nit, we usually compare with 0 explicitly, '!= 0', and avoid implicit casts. > + lua_pushnumber(L, f->clock_acc / (double)cord()->clock_acc * 100); > + else > + lua_pushnumber(L, 0); > lua_settable(L, -3); > + > lua_pushliteral(L, "instant"); > - lua_pushnumber(L, f->clock_delta_last / (double)cord()->clock_delta_last * 100); > + if (cord()->clock_delta_last) > + lua_pushnumber(L, f->clock_delta_last / (double)cord()->clock_delta_last * 100); > + else > + lua_pushnumber(L, 0); > lua_settable(L, -3); > + > lua_pushliteral(L, "time"); > lua_pushnumber(L, f->cputime / (double) FIBER_TIME_RES); > lua_settable(L, -3); >