From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC14625228C; Wed, 17 Dec 2025 19:06:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765998413; cv=none; b=nxyI5hHGHGqQIqTeTQP2AkmDzYTz0S2nW9K3geZYnnYc0LD2HBGPWsnnOivHx/c1aIz3kxrYMl1rCKzdTh/npfVbUqINsUAdOsiy3KA872gTFC7U37WjklZABMypEo0yldqZ3YCFKAOnd6ii6x/XVV/TIpavCW1edHScDoUqWUs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765998413; c=relaxed/simple; bh=ocLUpl3wFK1ZMS5TR7Bm+xXLxFSu2+wCSVjFjs1Bj0I=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ROAd79CwAkzQCaQ7OPMA/q4NfrprKC6ChonpKi9FHHWJvnre+FVvJEsoLblWwtBSh9zu1Q8AMAz0OrtaOM/xNnRu23ES88HK1UrKmwyba6z0eCpzRSzuvfeW294qNdm/JJCUPlytWEPDuazSsUhJB/cHg7LoTWqZflhDELExtbg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 96BD28B79A; Wed, 17 Dec 2025 19:06:42 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf20.hostedemail.com (Postfix) with ESMTPA id 49E1C20032; Wed, 17 Dec 2025 19:06:40 +0000 (UTC) Date: Wed, 17 Dec 2025 14:08:16 -0500 From: Steven Rostedt To: Ian Rogers Cc: LKML , Linux Trace Kernel , Masami Hiramatsu , Mathieu Desnoyers , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Peter Zijlstra Subject: Re: [PATCH] tracing: Allow perf to read synthetic events Message-ID: <20251217140816.23a8a1bc@gandalf.local.home> In-Reply-To: References: <20251217113920.50b56246@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: qtho7xynzp3ftwjenw6xce4qwowxaksb X-Rspamd-Server: rspamout03 X-Rspamd-Queue-Id: 49E1C20032 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+j6H2HWjzjQ9F47pkveouItVJb9wqD+IE= X-HE-Tag: 1765998400-940074 X-HE-Meta: U2FsdGVkX1+vfazomHCj7uCgpgKgUW+69i7rD3+vFx4gYBxegbUb1oCGGEWVN/9VIPnoU1NGE6hm81FeGEaUvqVjocbG5vRS2DvIRcBosfNaqpBWdg0BvQFwm5gO2nR/JGLfDpDvkE/jIJXofnjBaJHR8laIrBfVZ3i5E05DumL4peFY3Kv/c5iZcBytRTPk87p9bP/pWw+UoXX26Q648nSdAPFvte4XB7AKyGYA0jgJcPJSN+u6GdoNM+jrLkeogw53cFO57bdPojvf2GuPsoC37wkVHqid9HEB69KnoF0ZlseVBboCObj6epcU44/i2QruKJW8xOIXHODgv34t8HPFOA1S/1D8 On Wed, 17 Dec 2025 10:58:25 -0800 Ian Rogers wrote: > This is great! Any chance of an example of using it? I'd like to add a test. I tested it with: # trace-cmd sqlhist -e -n futex_wait select TIMESTAMP_DELTA_USECS as lat from sys_enter_futex as start join sys_exit_futex as end on start.common_pid = end.common_pid # perf record -e synthetic:futex_wait # perf script bash 1043 [002] 49.501707: synthetic:futex_wait: lat=8 in:imuxsock 610 [005] 58.904344: synthetic:futex_wait: lat=27 rs:main Q:Reg 612 [007] 58.904478: synthetic:futex_wait: lat=10847333 rs:main Q:Reg 612 [007] 58.904507: synthetic:futex_wait: lat=6 ls 1050 [004] 59.283561: synthetic:futex_wait: lat=8 in:imklog 611 [004] 69.084959: synthetic:futex_wait: lat=55 rs:main Q:Reg 612 [007] 69.085014: synthetic:futex_wait: lat=10180378 rs:main Q:Reg 612 [007] 69.085041: synthetic:futex_wait: lat=5 But feel free to use any other synthetic event or perf command. -- Steve