From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0CEA35A117; Wed, 11 Sep 2024 14:23:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726064589; cv=none; b=jkyE+qvHYFbjpYFgBeh0CMTONTVyJQDTXjUbr1dJtg1Ze7SpWdx/4EWnW4FEllGauC/+OvYw9bC34iTVVG8DWkwHR612jTPgRB9zNX4IkVhOmg0cLqCxnYnupFfWh/J6XrZ3zrtCTWTE3oRYDkC4qyf8ReP2CDuFlDLdmRlk6mo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726064589; c=relaxed/simple; bh=1exqtszE8qg/zfZb+SPj6gWdkiOR6leFN4ai47Xb0kk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PxSUZO48dba/JZONwrndw2Dx7fSjZC3C+ynlUepqhn5xYRDmcWWzMnwcbmRZP+8S9+a94guD4slcW5z9Un9ipd75ETNTKwawkjXQeLrQ+SFf4rR2mHxWhqGzZNnxLCtmtmW+6xm66rDjPTlyLud4VoQjf/h7R5MmVkjTA5rNjS8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KvHJwRjj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KvHJwRjj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EEEBC4CEC5; Wed, 11 Sep 2024 14:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726064588; bh=1exqtszE8qg/zfZb+SPj6gWdkiOR6leFN4ai47Xb0kk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KvHJwRjjZH5cwboPM+g02ORXGnBqFqIm4SesJjZBJbVktyjXP2Mauteiw0enylzEA juMyyCcedwHTpsN/EuJZxdvHXYnbEQMf6hPk9DAxPCIdv4+z7ttmitMAhgY7GkdAWO WGhtlQb6qfq/G5BxnVxFyZ2erLIRwcQmZxwFl6Yd0e11QKty84GI29jTlZF+Cm54hb WNuCDc5R+ty1KldeNCDOJGUKqFdSvmPO9k13fXAGlV87dE9qvmN1I6r8Sv5pWmng8O c0W7dW8AcMGdxFtyzNojRX7rH2aTK3LeyOYo6ouVabBm+wXPHTWsDlM85cvPPiTDTf M8+q8DT2yDdYw== Date: Wed, 11 Sep 2024 11:23:05 -0300 From: Arnaldo Carvalho de Melo To: Howard Chu Cc: adrian.hunter@intel.com, irogers@google.com, jolsa@kernel.org, kan.liang@linux.intel.com, namhyung@kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo Subject: Re: [PATCH v3 6/8] perf trace: Collect augmented data using BPF Message-ID: References: <20240824163322.60796-1-howardchu95@gmail.com> <20240824163322.60796-7-howardchu95@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Wed, Sep 04, 2024 at 02:11:35PM -0700, Howard Chu wrote: > On Wed, Sep 4, 2024 at 12:53 PM Arnaldo Carvalho de Melo wrote: > > On Sun, Aug 25, 2024 at 12:33:20AM +0800, Howard Chu wrote: > > ⬢[acme@toolbox perf-tools-next]$ pahole -C syscall_enter_args /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o > > struct syscall_enter_args { > > unsigned long long common_tp_fields; /* 0 8 */ > > long syscall_nr; /* 8 8 */ > > unsigned long args[6]; /* 16 48 */ > > > > /* size: 64, cachelines: 1, members: 3 */ > > }; > > > > So the entry has the theoretical max limit for the augmented payload > > which would be 6 * sizeof(struct augmented_arg) + the common header for > > tracepoints (unaugmented), a lot of space, but... > > Yes, if I don't use this much space, and try to do a flexible payload > length, I won't be able to pass the BPF verifier. I will try to fix > this wasting problem. But then we don't use it, I need to look at the implementation of BPF maps, to see how bad is this, but I doubt it is that much, well see. - Arnaldo