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 0B354CA0EC3 for ; Tue, 12 Sep 2023 12:22:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234391AbjILMXB (ORCPT ); Tue, 12 Sep 2023 08:23:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231127AbjILMXA (ORCPT ); Tue, 12 Sep 2023 08:23:00 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 862F710D5 for ; Tue, 12 Sep 2023 05:22:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694521329; 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=CDEPHFopRZA+PuiZRei3lkTc2CBm4TBtrZiF0tF5PU0=; b=B/m5a4Tt1yDGXbF6KuJ1TVmaP2r8xXu9OXgSZTziiIHKD9EeHfEnIRW9OnAop3OMWrxLcq vZrVyy35+9fqh7dZXE74cMP8J1qWL/sDTQqyUL1QK7T4GkXdT8sMT60sy8EZ7jXe0+afbY ouVaYzn3AFh3XyHF/H00KY8YR55broI= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-533-RuqSgqdtPSGiXNcA801LVA-1; Tue, 12 Sep 2023 08:22:08 -0400 X-MC-Unique: RuqSgqdtPSGiXNcA801LVA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E5E443800BD2; Tue, 12 Sep 2023 12:22:07 +0000 (UTC) Received: from Diego (unknown [10.39.208.41]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A5B0A40C6EA8; Tue, 12 Sep 2023 12:22:06 +0000 (UTC) Date: Tue, 12 Sep 2023 14:22:04 +0200 (CEST) From: Michael Petlan X-X-Sender: Michael@Diego To: vmolnaro@redhat.com cc: linux-perf-users@vger.kernel.org, acme@kernel.org, acme@redhat.com Subject: Re: [PATCH 2/2] perf test stat+shadow_stat.sh: Add threshold for rounding errors In-Reply-To: <20230912121926.12111-2-vmolnaro@redhat.com> Message-ID: References: <20230912121926.12111-1-vmolnaro@redhat.com> <20230912121926.12111-2-vmolnaro@redhat.com> User-Agent: Alpine 2.20 (LRH 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Tue, 12 Sep 2023, vmolnaro@redhat.com wrote: > From: Veronika Molnarova > > The test was failing in specific scenarios due to imperfection of FP > arithmetics. The `bc` command wasn't correctly rounding the result > of division causing the failure. > > Replace the `bc` with `awk` which should work with more decimal > places and add a threshold to catch any possible rounding errors. > The acceptable rounding error is set to 0.01 when the test > passes with a warning message. Acked-by: Michael Petlan > --- > tools/perf/tests/shell/stat+shadow_stat.sh | 30 +++++++++++++++++----- > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/tools/perf/tests/shell/stat+shadow_stat.sh b/tools/perf/tests/shell/stat+shadow_stat.sh > index 0e9cba84e75..73c990fe5ee 100755 > --- a/tools/perf/tests/shell/stat+shadow_stat.sh > +++ b/tools/perf/tests/shell/stat+shadow_stat.sh > @@ -4,6 +4,8 @@ > > set -e > > +TRESHOLD=0.015 > + > # skip if system-wide mode is forbidden > perf stat -a true > /dev/null 2>&1 || exit 2 > > @@ -33,10 +35,18 @@ test_global_aggr() > fi > > # use printf for rounding and a leading zero > - res=`printf "%.2f" "$(echo "scale=6; $num / $cyc" | bc -q)"` > + res=`echo $num $cyc | awk '{printf "%.2f", $1 / $2}'` > if [ "$ipc" != "$res" ]; then > - echo "IPC is different: $res != $ipc ($num / $cyc)" > - exit 1 > + # check the difference from the real result for FP imperfections > + diff=`echo $ipc $res $TRESHOLD | \ > + awk '{x = ($1 - $2) < 0 ? ($2 - $1) : ($1 - $2); print (x > $3)}'` > + > + if [ $diff -eq 1 ]; then > + echo "IPC is different: $res != $ipc ($num / $cyc)" > + exit 1 > + fi > + > + echo "Warning: Difference of IPC is under the treshold" > fi > done > } > @@ -67,10 +77,18 @@ test_no_aggr() > fi > > # use printf for rounding and a leading zero > - res=`printf "%.2f" "$(echo "scale=6; $num / $cyc" | bc -q)"` > + res=`echo $num $cyc | awk '{printf "%.2f", $1 / $2}'` > if [ "$ipc" != "$res" ]; then > - echo "IPC is different for $cpu: $res != $ipc ($num / $cyc)" > - exit 1 > + # check difference from the real result for FP imperfections > + diff=`echo $ipc $res $TRESHOLD | \ > + awk '{x = ($1 - $2) < 0 ? ($2 - $1) : ($1 - $2); print (x > $3)}'` > + > + if [ $diff -eq 1 ]; then > + echo "IPC is different: $res != $ipc ($num / $cyc)" > + exit 1 > + fi > + > + echo "Warning: Difference of IPC is under the treshold" > fi > done > } > -- > 2.41.0 > >