From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1B56C433EF for ; Tue, 18 Jan 2022 22:40:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344949AbiARWkX convert rfc822-to-8bit (ORCPT ); Tue, 18 Jan 2022 17:40:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344927AbiARWkW (ORCPT ); Tue, 18 Jan 2022 17:40:22 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6220C061574 for ; Tue, 18 Jan 2022 14:40:22 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E8D7C6143D for ; Tue, 18 Jan 2022 22:40:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 081FEC340E0; Tue, 18 Jan 2022 22:40:20 +0000 (UTC) Date: Tue, 18 Jan 2022 17:40:19 -0500 From: Steven Rostedt To: Yordan Karadzhov Cc: Linux Trace Devel Subject: Re: [PATCH v3] trace-cruncher: Add API to set tracing CPU affinity Message-ID: <20220118174019.005afcc2@gandalf.local.home> In-Reply-To: <3a60bdb7-6d2c-a912-3ef1-880ff9388a52@gmail.com> References: <20220117201835.0991759f@gandalf.local.home> <3a60bdb7-6d2c-a912-3ef1-880ff9388a52@gmail.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Tue, 18 Jan 2022 12:08:44 +0200 Yordan Karadzhov wrote: > On 18.01.22 г. 3:18 ч., Steven Rostedt wrote: > > diff --git a/examples/reset-affinity.py b/examples/reset-affinity.py > > new file mode 100755 > > index 0000000..2bca32e > > --- /dev/null > > +++ b/examples/reset-affinity.py > > @@ -0,0 +1,5 @@ > > +#!/usr/bin/env python3 > > + > > +import tracecruncher.ftracepy as ft > > + > > +ft.reset_affinity(); > > diff --git a/examples/test-affinity.py b/examples/test-affinity.py > > new file mode 100755 > > index 0000000..1619931 > > --- /dev/null > > +++ b/examples/test-affinity.py > > @@ -0,0 +1,5 @@ > > +#!/usr/bin/env python3 > > + > > +import tracecruncher.ftracepy as ft > > + > > +ft.set_affinity(cpus=["0-1","3"]); > > diff --git a/src/ftracepy-utils.c b/src/ftracepy-utils.c > > index a735d88..e42f69c 100644 > > --- a/src/ftracepy-utils.c > > +++ b/src/ftracepy-utils.c > > @@ -2394,6 +2394,99 @@ PyObject *PyFtrace_hist(PyObject *self, PyObject *args, > > return NULL; > > } > > > > +PyObject *PyFtrace_reset_affinity(PyObject *self, PyObject *args, > > + PyObject *kwargs) > > +{ > > + struct tracefs_instance *instance; > > + static char *kwlist[] = {"instance", NULL}; > > + PyObject *py_inst = NULL; > > + int ret; > > + > > + if (!PyArg_ParseTupleAndKeywords(args, > > + kwargs, > > + "|O", > > + kwlist, > > + &py_inst)) { > > + return NULL; > > + } > > + > > + if (!get_optional_instance(py_inst, &instance)) > > + goto err; > > No need to have 'goto' in this function. Just return NULL (see also my comment at the bottom). > > > > + > > + /* NULL for CPUs will set all available CPUS */ > > + ret = tracefs_instance_set_affinity(instance, NULL); > > + if (ret < 0) { > > + PyErr_SetString(TRACECRUNCHER_ERROR, > > + "Failed to reset tracing affinity."); > > + goto err; > > + } > > Can we make the call of tracefs_instance_set_affinity(), the error check and the error message a static helper? > I will explain why bellow in the patch. > > > + > > + Py_RETURN_NONE; > > +err: > > + return NULL; > > +} > > + > > +PyObject *PyFtrace_set_affinity(PyObject *self, PyObject *args, > > + PyObject *kwargs) > > +{ > > + struct tracefs_instance *instance; > > + static char *kwlist[] = {"cpus", "instance", NULL}; > > + PyObject *py_cpus; > > + PyObject *py_inst = NULL; > > + const char *cpu_str; > > + int ret; > > + > > + if (!init_print_seq()) > > + return false; > > We have to return NULL here. Oops, silly cut and paste issue. > > > + > > + if (!PyArg_ParseTupleAndKeywords(args, > > + kwargs, > > + "O|O", > > + kwlist, > > + &py_cpus, > > + &py_inst)) { > > + return NULL; > > + } > > + > > + if (PyUnicode_Check(py_cpus)) { > > + cpu_str = (const char *)PyUnicode_DATA(py_cpus); > > And here we can have > > if ((is_all(cpu_str) { > Call the static helper for 'reset' here and return. Do we need a static helper? It is simply: tracefs_instance_set_affinity(instance, NULL); and that will set all of them. (NULL for CPUs means all CPUs). > } > > > + if (trace_seq_puts(&seq, cpu_str) < > + goto err_seq; > > + } else if (PyList_CheckExact(py_cpus)) { > > + int i, n = PyList_Size(py_cpus); > > + > > + for (i = 0; i < n; ++i) { > > + cpu_str = str_from_list(py_cpus, i); > > + if (i) > > + trace_seq_putc(&seq, ','); > > + if (trace_seq_puts(&seq, cpu_str) < 0) > > + goto err_seq; > > + } > > + } else { > > + PyErr_SetString(TRACECRUNCHER_ERROR, > > + "Invalid \"cpus\" type."); > > It may be better to use TfsError_fmt() here. > This helper will print also the error log of libtracefs. > The same comment applies for all error messages below. Do we want that as the error log will not be modified by this operation. > > > + goto err; > return NULL; > > + } > > + > > + if (!get_optional_instance(py_inst, &instance)) > > + goto err; > return NULL; > > + > > + trace_seq_terminate(&seq); > > + ret = tracefs_instance_set_affinity(instance, seq.buffer); > > + if (ret < 0) { > > + PyErr_SetString(TRACECRUNCHER_ERROR, > > + "Invalid \"cpus\" argument."); > > + goto err; > return NULL; > > + } > > + > > + Py_RETURN_NONE; > > +err_seq: > > + PyErr_SetString(TRACECRUNCHER_ERROR, > > + "Internal processing string error."); > > +err: > > + return NULL; > > I guess you use 'goto err;' everywhere, because you want to stress that returning NULL is essentially exiting with > error. However, so far we used just 'return NULL' everywhere and I would prefer to keep the code consistent. > Maybe in a separate patch we can replace all ''return NULL;' lines with a macro that can have some self-explanatory name? Yeah, I was trying to match the existing code, as I'm new to this. ;-) -- Steve