From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 22D6822316 for ; Mon, 20 Nov 2023 17:38:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q14/AOXc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0556C433C7; Mon, 20 Nov 2023 17:38:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700501908; bh=p+qhJD+a7A3Vn/YfBl7sYkUwHQd9/SQ5vepUL1GP/yQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Q14/AOXcjMkB61wedVH7lSliHDiWjFiXW/o5mSEYxehrFQ6nOqL09FbATSCnPi/da d3uZ8enBfmTYRYn7f6pL1RRwUdHOgCj3EV81fJZl02jUhgdibA0RmEDSU7hPgrz+kv UR/IFQ0CYls7B7+2N09WL/AW2P5SADPTplCl833sdBlR9Vel/KTbLAtVNmMwAlUWjj dNYHxyPxSjZsSK5AJ4oMdGZr2vADwt+xgRjwsTfhMjesKDwvc1Kcc+7h54l9CPlbcW 3SPTPffZoWCabbt+5yHhxXEhzmB9XfRvVzXM8JbkMhSJcj6lQ9vlIkjpQHprWdSkD+ M72pj0y61HdLw== Date: Mon, 20 Nov 2023 17:38:23 +0000 From: Simon Horman To: Pedro Tammela Cc: netdev@vger.kernel.org, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, shuah@kernel.org, victor@mojatatu.com Subject: Re: [PATCH net-next 1/6] selftests: tc-testing: cap parallel tdc to 4 cores Message-ID: <20231120173823.GF245676@kernel.org> References: <20231117171208.2066136-1-pctammela@mojatatu.com> <20231117171208.2066136-2-pctammela@mojatatu.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231117171208.2066136-2-pctammela@mojatatu.com> On Fri, Nov 17, 2023 at 02:12:03PM -0300, Pedro Tammela wrote: > We have observed a lot of lock contention and test instability when running with >8 cores. > Enough to actually make the tests run slower than with fewer cores. > > Cap the maximum cores of parallel tdc to 4 which showed in testing to > be a reasonable number for efficiency and stability in different kernel > config scenarios. > > Signed-off-by: Pedro Tammela Hi Pedro, This limit seems a bit unfortunate, because it seems dependent on hardware and software details that are subject to change. Meanwhile this patch will be long since forgotten. But, OTOH, I can't think of a better idea at this time, so: Reviewed-by: Simon Horman ...