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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47BCDC433E0 for ; Mon, 8 Jun 2020 17:18:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EA59206C3 for ; Mon, 8 Jun 2020 17:18:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387558AbgFHRSe (ORCPT ); Mon, 8 Jun 2020 13:18:34 -0400 Received: from mga11.intel.com ([192.55.52.93]:11556 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730490AbgFHRSe (ORCPT ); Mon, 8 Jun 2020 13:18:34 -0400 IronPort-SDR: a3VqVDuymn6feG2Lo5OmZ4Je/ZeEvuOhQSaVo2lMOnSCVDRRff6VEbUOIpoWbMkS3vhVU8K68a f6CAexxa6VdA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2020 10:18:23 -0700 IronPort-SDR: Uy4yUQVcIWJioG2l+9Un+d+JXQeqZ6d9HIW6Sq+NGewyJe+CuXofcE+/e358jXJNq1pMRlttkQ LwQI+WDxMWYg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,487,1583222400"; d="scan'208";a="446809845" Received: from linux.intel.com ([10.54.29.200]) by orsmga005.jf.intel.com with ESMTP; 08 Jun 2020 10:18:23 -0700 Received: from [10.249.230.149] (abudanko-mobl.ccr.corp.intel.com [10.249.230.149]) by linux.intel.com (Postfix) with ESMTP id 8F5C9580458; Mon, 8 Jun 2020 10:18:21 -0700 (PDT) Subject: Re: [PATCH v7 01/13] tools/libperf: introduce notion of static polled file descriptors From: Alexey Budankov To: Jiri Olsa Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel References: <5de4b954-24f0-1e8d-5a0d-7b12783b8218@linux.intel.com> <3c92a0ad-d7d3-4e78-f0b8-1d3a7122c69e@linux.intel.com> <20200605105051.GA1404794@krava> <20200605113834.GC1404794@krava> <49eca46e-4d0e-2ae5-d7d9-e37a4d680270@linux.intel.com> <20200608084344.GA1520715@krava> <2d80a43a-54cf-3d12-92fd-066217c95d76@linux.intel.com> <20200608160758.GD1558310@krava> <345e3f6e-627d-89fc-364d-59f76071ccaa@linux.intel.com> Organization: Intel Corp. Message-ID: <6a861ce4-3769-fc2a-5f9d-3003238a9736@linux.intel.com> Date: Mon, 8 Jun 2020 20:18:20 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <345e3f6e-627d-89fc-364d-59f76071ccaa@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08.06.2020 19:43, Alexey Budankov wrote: > > On 08.06.2020 19:07, Jiri Olsa wrote: >> On Mon, Jun 08, 2020 at 12:54:31PM +0300, Alexey Budankov wrote: >>> >>> On 08.06.2020 11:43, Jiri Olsa wrote: >>>> On Mon, Jun 08, 2020 at 11:08:56AM +0300, Alexey Budankov wrote: >>>>> >>>>> On 05.06.2020 19:15, Alexey Budankov wrote: >>>>>> >>>>>> On 05.06.2020 14:38, Jiri Olsa wrote: >>>>>>> On Fri, Jun 05, 2020 at 12:50:54PM +0200, Jiri Olsa wrote: >>>>>>>> On Wed, Jun 03, 2020 at 06:52:59PM +0300, Alexey Budankov wrote: >>>>>>>>> >>>>>>>>> Implement adding of file descriptors by fdarray__add_stat() to >>>>>>>>> fix-sized (currently 1) stat_entries array located at struct fdarray. >>>>>>>>> Append added file descriptors to the array used by poll() syscall >>>>>>>>> during fdarray__poll() call. Copy poll() result of the added >>>>>>>>> descriptors from the array back to the storage for analysis. >>>>>>>>> >>>>>>>>> Signed-off-by: Alexey Budankov >>>>>>>>> --- >>>>>>>>> tools/lib/api/fd/array.c | 42 +++++++++++++++++++++++- >>>>>>>>> tools/lib/api/fd/array.h | 7 ++++ >>>>>>>>> tools/lib/perf/evlist.c | 11 +++++++ >>>>>>>>> tools/lib/perf/include/internal/evlist.h | 2 ++ >>>>>>>>> 4 files changed, 61 insertions(+), 1 deletion(-) >>>>>>>>> >>>>>>>>> diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c >>>>>>>>> index 58d44d5eee31..b0027f2169c7 100644 >>>>>>>>> --- a/tools/lib/api/fd/array.c >>>>>>>>> +++ b/tools/lib/api/fd/array.c >>>>>>>>> @@ -11,10 +11,16 @@ >>>>>>>>> >>>>>>>>> void fdarray__init(struct fdarray *fda, int nr_autogrow) >>>>>>>>> { >>>>>>>>> + int i; >>>>>>>>> + >>>>>>>>> fda->entries = NULL; >>>>>>>>> fda->priv = NULL; >>>>>>>>> fda->nr = fda->nr_alloc = 0; >>>>>>>>> fda->nr_autogrow = nr_autogrow; >>>>>>>>> + >>>>>>>>> + fda->nr_stat = 0; >>>>>>>>> + for (i = 0; i < FDARRAY__STAT_ENTRIES_MAX; i++) >>>>>>>>> + fda->stat_entries[i].fd = -1; >>>>>>>>> } >>>>>>>>> >>>>>>>>> int fdarray__grow(struct fdarray *fda, int nr) >>>>>>>>> @@ -83,6 +89,20 @@ int fdarray__add(struct fdarray *fda, int fd, short revents) >>>>>>>>> return pos; >>>>>>>>> } >>>>>>>>> >>>>>>>>> +int fdarray__add_stat(struct fdarray *fda, int fd, short revents) >>>>>>>>> +{ >>>>>>>>> + int pos = fda->nr_stat; >>>>>>>>> + >>>>>>>>> + if (pos >= FDARRAY__STAT_ENTRIES_MAX) >>>>>>>>> + return -1; >>>>>>>>> + >>>>>>>>> + fda->stat_entries[pos].fd = fd; >>>>>>>>> + fda->stat_entries[pos].events = revents; >>>>>>>>> + fda->nr_stat++; >>>>>>>>> + >>>>>>>>> + return pos; >>>>>>>>> +} >>>>>>>>> + >>>>>>>>> int fdarray__filter(struct fdarray *fda, short revents, >>>>>>>>> void (*entry_destructor)(struct fdarray *fda, int fd, void *arg), >>>>>>>>> void *arg) >>>>>>>>> @@ -113,7 +133,27 @@ int fdarray__filter(struct fdarray *fda, short revents, >>>>>>>>> >>>>>>>>> int fdarray__poll(struct fdarray *fda, int timeout) >>>>>>>>> { >>>>>>>>> - return poll(fda->entries, fda->nr, timeout); >>>>>>>>> + int nr, i, pos, res; >>>>>>>>> + >>>>>>>>> + nr = fda->nr; >>>>>>>>> + >>>>>>>>> + for (i = 0; i < fda->nr_stat; i++) { >>>>>>>>> + if (fda->stat_entries[i].fd != -1) { >>>>>>>>> + pos = fdarray__add(fda, fda->stat_entries[i].fd, >>>>>>>>> + fda->stat_entries[i].events); >>>>>>>> >>>>>>>> so every call to fdarray__poll will add whatever is >>>>>>>> in stat_entries to entries? how is it removed? >>>>>>>> >>>>>>>> I think you should either follow what Adrian said >>>>>>>> and put 'static' descriptors early and check for >>>>>>>> filter number to match it as an 'quick fix' >>>>>>>> >>>>>>>> or we should fix it for real and make it generic >>>>>>>> >>>>>>>> so currently the interface is like this: >>>>>>>> >>>>>>>> pos1 = fdarray__add(a, fd1 ... ); >>>>>>>> pos2 = fdarray__add(a, fd2 ... ); >>>>>>>> pos3 = fdarray__add(a, fd2 ... ); >>>>>>>> >>>>>>>> fdarray__poll(a); >>>>>>>> >>>>>>>> num = fdarray__filter(a, revents, destructor, arg); >>>>>>>> >>>>>>>> when fdarray__filter removes some of the fds the 'pos1,pos2,pos3' >>>>>>>> indexes are not relevant anymore >>>>>> >>>>>> and that is why the return value of fdarray__add() should be converted >>>>>> to bool (added/not added). Currently the return value is used as bool >>>>>> only allover the calling code. >>>>>> >>>>>> fdarray__add_fixed() brings the notion of fd with fixed pos which is >>>>>> valid after fdarray__add_fixed() call so the pos could be used to access >>>>>> pos fd poll status after poll() call. >>>>>> >>>>>> pos = fdarray__add_fixed(array, fd); >>>>>> fdarray_poll(array); >>>>>> revents = fdarray_fixed_revents(array, pos); >>>>>> fdarray__del(array, pos); >>>>> >>>>> So how is it about just adding _revents() and _del() for fixed fds with >>>>> correction of retval to bool for fdarray__add()? >>>> >>>> I don't like the separation for fixed and non-fixed fds, >>>> why can't we make generic? >>> >>> Usage models are different but they want still to be parts of the same class >>> for atomic poll(). The distinction is filterable vs. not filterable. >>> The distinction should be somehow provided in API. Options are: >>> 1. expose separate API calls like __add_nonfilterable(), __del_nonfilterable(); >>> use nonfilterable quality in __filter() and __poll() and, perhaps, other internals; >>> 2. extend fdarray__add(, nonfilterable) with the nonfilterable quality >>> use the type in __filter() and __poll() and, perhaps, other internals; >>> expose less API calls in comparison with option 1 >>> >>> Exposure of pos for filterable fds should be converted to bool since currently >>> the returned pos can become stale and there is no way in API to check its state. >>> So it could look like this: >>> >>> fdkey = fdarray__add(array, fd, events, type) >>> type: filterable, nonfilterable, somthing else >>> revents = fdarray__get_revents(fdkey); >>> fdarray__del(array, fdkey); >> >> I think there's solution without having filterable type, > > and still making the atomic fdarray__poll()? How is it about design like this? int fdarray__poll(struct fdarray *fda, int timeout) with additional external array of fds to simultaneously poll() on: int fdarray__poll(struct fdarray *fda, int timeout, int *fds, size_t fds_size) fds would be added to array just prior poll() call. That wouldn't cause fdarray class extension with fd types and wouldn't change fdarray__filter() keeping the types processing outside of fdarray and libperf. Adoption of new fdarray__poll() signature in the tool via macro (or inline function): #define fdarray__poll(fda, timeout) \ fdarray__poll_ext(fda, timeout, NULL, 0) int fdarray__poll_ext(struct fdarray *fda, int timeout, int *fds, size_t fds_size) ~Alexey