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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 B29EAC433E0 for ; Fri, 8 Jan 2021 13:54:55 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CE93A238E8 for ; Fri, 8 Jan 2021 13:54:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE93A238E8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7774D88007; Fri, 8 Jan 2021 13:54:52 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6B1ED6E822 for ; Fri, 8 Jan 2021 13:54:49 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 23538769-1500050 for multiple; Fri, 08 Jan 2021 13:54:36 +0000 MIME-Version: 1.0 In-Reply-To: References: <20210107221724.10036-1-chris@chris-wilson.co.uk> <161011238272.28368.13711350036924329757@build.alporthouse.com> From: Chris Wilson To: Andi Shyti Date: Fri, 08 Jan 2021 13:54:35 +0000 Message-ID: <161011407580.28368.6023725628158257155@build.alporthouse.com> User-Agent: alot/0.9 Subject: Re: [Intel-gfx] [PATCH 1/5] drm/i915/selftests: Skip unstable timing measurements X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Quoting Andi Shyti (2021-01-08 13:51:54) > Hi Chris, > > > > > diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c > > > > index 75839db63bea..59c58a276677 100644 > > > > --- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c > > > > +++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c > > > > @@ -852,6 +852,9 @@ static int _perf_memcpy(struct intel_memory_region *src_mr, > > > > } > > > > > > > > sort(t, ARRAY_SIZE(t), sizeof(*t), wrap_ktime_compare, NULL); > > > > + if (!t[0]) > > > > + continue; > > > > + > > > > > > are you assuming here that if t[0] is '0', also the rest of 't' > > > is '0'? > > > > It's sorted into ascending order with ktime_t... Hmm, s64 not u64 as I > > presumed. So better to check <= 0. > > by division by 0 I guess you mean here: > > div64_u64(mul_u32_u32(4 * size, > 1000 * 1000 * 1000), > t[1] + 2 * t[2] + t[3]) >> 20); > > why are you testing t[0]? Did I miss anything else? Since t[0] is the most negative value, if it is <= 0 that implies at least one of the measurements was bad. If any are bad, all are bad by association. I considered checking t[4] to make sure that at least the best was good enough, but paranoia won. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx