[{"id":33279,"web_url":"https://patchwork.libcamera.org/comment/33279/","msgid":"","date":"2025-02-03T19:25:27","subject":"Re: [RFC PATCH v3 04/21] apps: common: event_loop: Use single event\n\tsource for deferred calls","submitter":{"id":143,"url":"https://patchwork.libcamera.org/api/people/143/","name":"Jacopo Mondi","email":"jacopo.mondi@ideasonboard.com"},"content":"Hi Barnabás\n\nOn Thu, Jan 30, 2025 at 11:50:23AM +0000, Barnabás Pőcze wrote:\n> Instead of calling `event_base_once()` every time a deferred call\n> is added to the loop, create an event source at construction, and\n> simply trigger that when a new deferred call is scheduled.\n>\n> Signed-off-by: Barnabás Pőcze \n\nSorry, I've not replied to the previous version.\n\nNow that I understand it better I really like this\n\nReviewed-by: Jacopo Mondi \n\n> ---\n> src/apps/common/event_loop.cpp | 48 +++++++++++++++++-----------------\n> src/apps/common/event_loop.h | 5 +---\n> 2 files changed, 25 insertions(+), 28 deletions(-)\n>\n> diff --git a/src/apps/common/event_loop.cpp b/src/apps/common/event_loop.cpp\n> index bc8cf17ab..b6230f4ba 100644\n> --- a/src/apps/common/event_loop.cpp\n> +++ b/src/apps/common/event_loop.cpp\n> @@ -21,12 +21,35 @@ EventLoop::EventLoop()\n> \tevthread_use_pthreads();\n> \tbase_ = event_base_new();\n> \tinstance_ = this;\n> +\n> +\tcallsTrigger_ = event_new(base_, -1, EV_PERSIST, [](evutil_socket_t, short, void *closure) {\n> +\t\tauto *self = static_cast(closure);\n> +\n> +\t\tfor (;;) {\n> +\t\t\tstd::function call;\n> +\n> +\t\t\t{\n> +\t\t\t\tstd::lock_guard locker(self->lock_);\n> +\t\t\t\tif (self->calls_.empty())\n> +\t\t\t\t\tbreak;\n> +\n> +\t\t\t\tcall = std::move(self->calls_.front());\n> +\t\t\t\tself->calls_.pop_front();\n> +\t\t\t}\n> +\n> +\t\t\tcall();\n> +\t\t}\n> +\t}, this);\n> +\tassert(callsTrigger_);\n> +\tevent_add(callsTrigger_, nullptr);\n> }\n>\n> EventLoop::~EventLoop()\n> {\n> \tinstance_ = nullptr;\n>\n> +\tevent_free(callsTrigger_);\n> +\n> \tevents_.clear();\n> \tevent_base_free(base_);\n> \tlibevent_global_shutdown();\n> @@ -57,7 +80,7 @@ void EventLoop::callLater(std::function &&func)\n> \t\tcalls_.push_back(std::move(func));\n> \t}\n>\n> -\tevent_base_once(base_, -1, EV_TIMEOUT, dispatchCallback, this, nullptr);\n> +\tevent_active(callsTrigger_, 0, 0);\n> }\n>\n> void EventLoop::addFdEvent(int fd, EventType type,\n> @@ -108,29 +131,6 @@ void EventLoop::addTimerEvent(const std::chrono::microseconds period,\n> \tevents_.push_back(std::move(event));\n> }\n>\n> -void EventLoop::dispatchCallback([[maybe_unused]] evutil_socket_t fd,\n> -\t\t\t\t [[maybe_unused]] short flags, void *param)\n> -{\n> -\tEventLoop *loop = static_cast(param);\n> -\tloop->dispatchCall();\n> -}\n> -\n> -void EventLoop::dispatchCall()\n> -{\n> -\tstd::function call;\n> -\n> -\t{\n> -\t\tstd::unique_lock locker(lock_);\n> -\t\tif (calls_.empty())\n> -\t\t\treturn;\n> -\n> -\t\tcall = calls_.front();\n> -\t\tcalls_.pop_front();\n> -\t}\n> -\n> -\tcall();\n> -}\n> -\n> EventLoop::Event::Event(std::function &&callback)\n> \t: callback_(std::move(callback)), event_(nullptr)\n> {\n> diff --git a/src/apps/common/event_loop.h b/src/apps/common/event_loop.h\n> index 760075885..aac5ed3cc 100644\n> --- a/src/apps/common/event_loop.h\n> +++ b/src/apps/common/event_loop.h\n> @@ -65,11 +65,8 @@ private:\n> \tint exitCode_;\n>\n> \tstd::deque> calls_;\n> +\t::event *callsTrigger_ = nullptr;\n>\n> \tstd::list> events_;\n> \tstd::mutex lock_;\n> -\n> -\tstatic void dispatchCallback(evutil_socket_t fd, short flags,\n> -\t\t\t\t void *param);\n> -\tvoid dispatchCall();\n> };\n> --\n> 2.48.1\n>\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 57DF4BD80A\n\tfor ;\n\tMon, 3 Feb 2025 19:25:34 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 891FE685AC;\n\tMon, 3 Feb 2025 20:25:33 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 493EC685A5\n\tfor ;\n\tMon, 3 Feb 2025 20:25:31 +0100 (CET)","from ideasonboard.com (93-61-96-190.ip145.fastwebnet.it\n\t[93.61.96.190])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id A0431514;\n\tMon, 3 Feb 2025 20:24:19 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"VrKlfSoP\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1738610659;\n\tbh=RKUGXwuH6sUP3WsXZjFfLxqZyz/kh8vc4jg4Xhc04es=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=VrKlfSoPO0RCx86NNfLv1+TOFK+y4AvuLhhICX4TF5EnXTx+W0N54abIy0tw4WyfT\n\tVwxT08hVfzJOxrAkI7qjoOTm2X1kBGw4bYiGwRjWKIbR55elgoCrJPWceYOBYleKWL\n\tbkr3Ne3Nl5Xiaxf67gKoFnT7qMD6LTFD9vf7Pcbs=","Date":"Mon, 3 Feb 2025 20:25:27 +0100","From":"Jacopo Mondi ","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Cc":"libcamera-devel@lists.libcamera.org","Subject":"Re: [RFC PATCH v3 04/21] apps: common: event_loop: Use single event\n\tsource for deferred calls","Message-ID":"","References":"<20250130115001.1129305-1-pobrn@protonmail.com>\n\t<20250130115001.1129305-5-pobrn@protonmail.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20250130115001.1129305-5-pobrn@protonmail.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]