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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 4132EC43461 for ; Tue, 6 Apr 2021 13:34:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D61761165 for ; Tue, 6 Apr 2021 13:34:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344528AbhDFNeo (ORCPT ); Tue, 6 Apr 2021 09:34:44 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:57474 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243941AbhDFNeh (ORCPT ); Tue, 6 Apr 2021 09:34:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617716069; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=h0Jdnzafbs6n+Z5KUUUKvvir1l+H0uK55dPK2XrwHg8=; b=YYeIPdXgCeXgJr7dge274/7OP7FhwVNkWqu3vIOJjHxRlDtGu+4/1Ya1aK9B8VGGsaXirs fusfovCxweIIKsy29IuISSunVvbX7aq1CU9NYVgfH/zJ8WcRUvE/rbSSU/4QFjvqb+1FO+ ntI/ZlSSNfk22ek6WoFj8kp1WkcHiNE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-500-JUHMKNzwPgWPqXPg9zEL_g-1; Tue, 06 Apr 2021 09:34:25 -0400 X-MC-Unique: JUHMKNzwPgWPqXPg9zEL_g-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1338C612AB; Tue, 6 Apr 2021 13:34:22 +0000 (UTC) Received: from krava (unknown [10.40.195.36]) by smtp.corp.redhat.com (Postfix) with SMTP id EB56D6EF42; Tue, 6 Apr 2021 13:34:17 +0000 (UTC) Date: Tue, 6 Apr 2021 15:34:16 +0200 From: Jiri Olsa To: John Garry Cc: will@kernel.org, mathieu.poirier@linaro.org, leo.yan@linaro.org, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, namhyung@kernel.org, irogers@google.com, linuxarm@huawei.com, kjain@linux.ibm.com, kan.liang@linux.intel.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, zhangshaokun@hisilicon.com, pc@us.ibm.com Subject: Re: [PATCH v2 2/6] perf test: Handle metric reuse in pmu-events parsing test Message-ID: References: <1616668398-144648-1-git-send-email-john.garry@huawei.com> <1616668398-144648-3-git-send-email-john.garry@huawei.com> <49025439-f9e3-0d32-b0a3-ff9f9ff71835@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49025439-f9e3-0d32-b0a3-ff9f9ff71835@huawei.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 06, 2021 at 02:21:11PM +0100, John Garry wrote: > On 06/04/2021 13:55, Jiri Olsa wrote: > > > > > So expr__find_other() may add a new item to pctx->ids, and we always iterate > > > > > again, and try to lookup any pmu_events, *, above. If none exist, then we > > > > hm, I don't see that.. so, what you do is: > > > > > > > > hashmap__for_each_entry_safe((&pctx->ids) ....) { > > > > > > > > rc = expr__find_other(pe->metric_expr, NULL, pctx, 0); > > > > } > > > > > > > > and what I think we need to do is: > > > > > > > > hashmap__for_each_entry_safe((&pctx->ids) ....) { > > > > > > > > rc = expr__find_other(pe->metric_expr, NULL, pctx, 0); > > > > > > > > break; > > > > } > > > > > > > > each time you resolve another metric, you need to restart > > > > the pctx->ids iteration, because there will be new items, > > > > and we are in the middle of it > > > Sure, but we will restart anyway. > > hum, where? you call expr__find_other and continue to next > > pctx->ids item > > We have: > > resolve_metric_simple() > { > bool all; > > do { > all = true; > > hashmap__for_each_entry_safe(&pctx->ids, ...) { > > pe = metricgroup_find_metric(cur->key, map); > if (!pe) > continue; > > ... > all = false; > > expr_del_id(pctx, cur->key); > > ... > rc = expr__find_other(pe->metric_expr, pctx); > if (rc) > goto out_err; > } > > } while (!all); > > } > > So once we evaluate a pmu_event in pctx->ids in @pe, @all is set false, and > we would loop again in the do-while loop, regardless of what > expr__find_other() does (apart from erroring), and so call > hashmap__for_each_entry_safe(&pctx->ids, ) again. ah ok, so it finishes the hash iteration first and then restarts it.. ok, I missed that, then it's fine > > This is really what is done in __resolve_metric() - indeed, I would use that > function directly, but it looks hard to extract that from metricgroup.c . yea, it's another world ;-) it's better to keep it separated thanks, jirka > > Thanks, > John > > > > > > Regardless of this, I don't think what I am doing is safe, i.e. adding new > > > items in the middle of the iter, so I will change in the way you suggest. > > it'll always add items in the middle of the iteration >