From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.gentoo.org (woodpecker.gentoo.org [140.211.166.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F42E28935C; Thu, 3 Jul 2025 04:01:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=140.211.166.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751515281; cv=none; b=r9uGbmkhDRiGD9hC+QmWP+I0kzWe1+0UQ8iPVygXdCMwKKHV8h+2SMdxprbBfghywpmhL2uZKw9GY4fvtnoSnjFrrj0cadPQ7dDRK6OuIXZymZayxDWaVEzSaEZ0+OVc3SwFqTZBKpIF45PFKQYjuugHu/uhbypyxmL1x0aizoQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751515281; c=relaxed/simple; bh=JpoUSlhJB82auXvu10Mi5QN6NRGkCsUApGJnLQme5SY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=YNbSR7p/YN3dbQXbl4dWEsBDjQSW2HC+afAu/odlVy/4L8/aS9VNjC/T1XqR4cfG/IzeXaayXDqbLj5WmeM7JdGNm6nworqwRVVyapcUrRoXKfYy3Ptffaej3u1wEsZnEI990RQRPRJGsX/BP6ULh4kHVWw1xL/i5u+UGv/O+TM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org; spf=pass smtp.mailfrom=gentoo.org; arc=none smtp.client-ip=140.211.166.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gentoo.org Received: from mop.sam.mop (unknown [82.8.138.118]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange secp256r1 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: sam) by smtp.gentoo.org (Postfix) with ESMTPSA id 4559E342138; Thu, 03 Jul 2025 04:01:15 +0000 (UTC) From: Sam James To: Namhyung Kim Cc: Steven Rostedt , fweimer@redhat.com, akpm@linux-foundation.org, andrii@kernel.org, axboe@kernel.dk, beaub@linux.microsoft.com, bpf@vger.kernel.org, indu.bhagat@oracle.com, jemarch@gnu.org, jolsa@kernel.org, jpoimboe@kernel.org, jremus@linux.ibm.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, x86@kernel.org Subject: Re: [PATCH v11 00/14] unwind_user: x86: Deferred unwinding infrastructure In-Reply-To: Organization: Gentoo References: <878ql9mlzn.fsf@oldenburg.str.redhat.com> <87wm8qlsuk.fsf@gentoo.org> <20250702121502.6e9d6102@batman.local.home> User-Agent: mu4e 1.12.11; emacs 31.0.50 Date: Thu, 03 Jul 2025 05:01:12 +0100 Message-ID: <87plehkjnb.fsf@gentoo.org> 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 Namhyung Kim writes: > On Wed, Jul 02, 2025 at 12:15:02PM -0400, Steven Rostedt wrote: >> On Wed, 02 Jul 2025 12:44:51 +0100 >> Sam James wrote: >> >> > In one of the commit messages in the perf series, Steven also gave >> > `perf record -g -vv true` which was convenient for making sure it's >> > correctly discovered deferred unwinding support. >> >> Although I posted the patch, the command "perf record -g -vv true" was >> Namhyung's idea. Just wanted to give credit where credit was due. > > Yep, it's to check if perf tool ask the deferred callchain to the > kernel. To check if the kernel returns the callchain properly is: > > $ perf report -D | grep -A5 CALLCHAIN_DEFERRED Thanks both. I'll update my notes and tinker more. > > Thanks, > Namhyung sam