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 8C3F213B58B; Mon, 9 Sep 2024 16:45:41 +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=1725900341; cv=none; b=rbiG6EJPKUY0CkGv8QWATmIzsgdJts2sAElc5qhEBp51eUAJtsw+EoL2m3EPP8TmbBC+9UhO3xXGHLwHjahyZwa5mJo9+ZqOCThBeS2zSAqjl98PNWnoOseVlBec0uQQKxQ9VayK8O1o9cvcL0ft2NFqr5j/E4vULlQK4RTzOxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725900341; c=relaxed/simple; bh=hpq8YITmQraxqj6xdNLOt80XvHmKvfAEgvJlnbW3QXw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LfFSrC51Eh0r6aqvRKVhnKLbgBa3fv2vBFk2Wcd8q+52ybmCAruu87YuF1xLyjQQGAMSaMgcogttAvq2a1pDUIsxx5gtEJDud8Iysirqokc0RET7ToObXXnoE1CsPoA+yMNE4L/fOjgLMUvkObalTmBDjJ95ZqyQ6crV1eJ9v78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Io48P0/A; 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="Io48P0/A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D7B7C4CEC5; Mon, 9 Sep 2024 16:45:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725900341; bh=hpq8YITmQraxqj6xdNLOt80XvHmKvfAEgvJlnbW3QXw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Io48P0/A89vA2jnpH3wkeM/81HeAUY0Yt3/qsdbnxXR4zkyszwwzcoQooCS4gC/g+ d0VK3IiSVwz5XA5+AFG/GYYw7ILTN6hfNFvFjCMCA0DT7fSAwEy/RRxlcwAxyHwPDB PDNbrP0RATDLE9vyEKI0hco/4ESYmUo2TFLmMuQuLxX2l4aupdT5JQEpyB+bS0skXA 26m7qa+Ie/TIRAT6jecUeAjOd62Zv+NJolLC2S3dDSSwUNitL21UDPI9MSelxsz+9j dPKVdFlRLFPxkGK4agkNElkV+gJ9hS8sS2QAztRH4TJwftf9zAMBuypPYv2sB8Qv1Z gKrjmPqH+mr0A== Date: Mon, 9 Sep 2024 13:45:36 -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 5/8] perf trace: Pretty print buffer data Message-ID: References: <20240824163322.60796-1-howardchu95@gmail.com> <20240824163322.60796-6-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=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Sep 09, 2024 at 01:33:17PM -0300, Arnaldo Carvalho de Melo wrote: > > static bool trace__filter_duration(struct trace *trace, double t) > > { > > return t < (trace->duration_filter * NSEC_PER_MSEC); > > @@ -1956,6 +1987,8 @@ syscall_arg_fmt__init_array(struct syscall_arg_fmt *arg, struct tep_format_field > > ((len >= 4 && strcmp(field->name + len - 4, "name") == 0) || > > strstr(field->name, "path") != NULL)) > > arg->scnprintf = SCA_FILENAME; > > + else if (strstr(field->type, "char *") && strstr(field->name, "buf")) > > + arg->scnprintf = SCA_BUF; > > You can't really do this for things like 'read' as we would be printing > whatever is in the buffer when we enter the syscall, right? As we can > see testing after applying the following patch: This is also valid for the struct dumper, where I'll have to add some indication in the syscall_fmt table when the pointer should be read in the BPF augmenter, and thus we shouldn't bother to get it in the sys_enter if it is, say, fstat(). - Arnaldo > root@number:~# perf trace -e read,write cat /etc/passwd > /dev/null > 0.000 ( 0.004 ms): cat/291442 read(fd: 3, buf: \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0, count: 832) = 832 > 0.231 ( 0.004 ms): cat/291442 read(fd: 3, buf: , count: 131072) = 3224 > 0.236 ( 0.001 ms): cat/291442 write(fd: 1, buf: root:x:0:0:Super User:/root:/bin, count: 3224) = 3224 > 0.239 ( 0.001 ms): cat/291442 read(fd: 3, buf: root:x:0:0:Super User:/root:/bin, count: 131072) = 0 > root@number:~# > > So we can't really do it at this point, we have to do it, for now, by > doing it on that syscall table initialization, for instance, for the > 'write' syscall: > > diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c > index 5f0877e891c2047d..1bcb45e737d830bf 100644 > --- a/tools/perf/builtin-trace.c > +++ b/tools/perf/builtin-trace.c > @@ -1379,6 +1379,8 @@ static const struct syscall_fmt syscall_fmts[] = { > .arg = { [2] = { .scnprintf = SCA_WAITID_OPTIONS, /* options */ }, }, }, > { .name = "waitid", .errpid = true, > .arg = { [3] = { .scnprintf = SCA_WAITID_OPTIONS, /* options */ }, }, }, > + { .name = "write", .errpid = true, > + .arg = { [1] = { .scnprintf = SCA_BUF, /* buf */ }, }, }, > }; > > static int syscall_fmt__cmp(const void *name, const void *fmtp) > @@ -1987,8 +1989,6 @@ syscall_arg_fmt__init_array(struct syscall_arg_fmt *arg, struct tep_format_field > ((len >= 4 && strcmp(field->name + len - 4, "name") == 0) || > strstr(field->name, "path") != NULL)) > arg->scnprintf = SCA_FILENAME; > - else if (strstr(field->type, "char *") && strstr(field->name, "buf")) > - arg->scnprintf = SCA_BUF; > else if ((field->flags & TEP_FIELD_IS_POINTER) || strstr(field->name, "addr")) > arg->scnprintf = SCA_PTR; > else if (strcmp(field->type, "pid_t") == 0) > > With that we get: > > root@number:~# perf trace -e read,write cat /etc/passwd > /dev/null > 0.000 ( 0.005 ms): cat/296870 read(fd: 3, buf: 0x7ffe9cb8df98, count: 832) = 832 > 0.268 ( 0.004 ms): cat/296870 read(fd: 3, buf: 0x7fa7d700a000, count: 131072) = 3224 > 0.273 ( 0.002 ms): cat/296870 write(fd: 1, buf: root:x:0:0:Super User:/root:/bin, count: 3224) = > 0.276 ( 0.001 ms): cat/296870 read(fd: 3, buf: 0x7fa7d700a000, count: 131072) = 0 > root@number:~# > > After the following patch is applied. > > - Arnaldo