Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755248AbbLKMP3 (ORCPT ); Fri, 11 Dec 2015 07:15:29 -0500 Received: from mail.kernel.org ([198.145.29.136]:46672 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753250AbbLKMPZ (ORCPT ); Fri, 11 Dec 2015 07:15:25 -0500 Date: Fri, 11 Dec 2015 09:15:21 -0300 From: Arnaldo Carvalho de Melo To: Wang Nan Cc: namhyung@kernel.org, linux-kernel@vger.kernel.org, pi3orama@163.com, mingo@kernel.org, lizefan@huawei.com, Alexei Starovoitov , Masami Hiramatsu Subject: Re: [PATCH v4 09/16] perf tools: Enable indices setting syntax for BPF maps Message-ID: <20151211121521.GQ17996@kernel.org> References: <1449541544-67621-1-git-send-email-wangnan0@huawei.com> <1449541544-67621-10-git-send-email-wangnan0@huawei.com> <20151211121145.GP17996@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151211121145.GP17996@kernel.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2013 Lines: 56 Em Fri, Dec 11, 2015 at 09:11:45AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Dec 08, 2015 at 02:25:37AM +0000, Wang Nan escreveu: > > This patch introduce a new syntax to perf event parser: > > > > # perf record -e bpf_file.c/maps.mymap.value[0,3...5,7]=1234/ ... > > Is the above example valid? Wouldn't this be "maps:mymap.value" ? > > > > > By utilizing the basic facilities in bpf-loader.c which allow setting > > different slots in a BPF map separately, the newly introduced syntax > > allows perf to control specific elements in a BPF map. > > > > Test result: > > > > # cat ./test_bpf_map_3.c > > /************************ BEGIN **************************/ > > #define SEC(NAME) __attribute__((section(NAME), used)) > > enum bpf_map_type { > > BPF_MAP_TYPE_ARRAY = 2, > > }; > > struct bpf_map_def { > > unsigned int type; > > unsigned int key_size; > > unsigned int value_size; > > unsigned int max_entries; > > }; > > static void *(*map_lookup_elem)(struct bpf_map_def *, void *) = > > (void *)1; > > static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = > > (void *)6; > > Can you explain the above a bit more? What are the magic 1 and 6 values? So, from another patch: static u64 (*bpf_ktime_get_ns)(void) = (void *)5; static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = (void *)6; static int (*bpf_get_smp_processor_id)(void) = (void *)8; static int (*bpf_perf_event_output)(void *, struct bpf_map_def *, int, void *, unsigned long) = (void *)23; Where can I get this magical mistery table? Could this be hidden away in some .h file automagically included in bpf scriptlets so that n00bies like me don't have to be wtf'ing? - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/