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 2DE8D17552 for ; Sat, 10 Aug 2024 07:04:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723273446; cv=none; b=M3BrUk9UodfnvUjm2ftJk283WkPUDr4tQCVdV5DdMRDMKVHP7f8BtS0HWObMKRIwk0i/0/YT1I5wpFzgXFc7P+lC5WO+rkc9Qiy+mVqyl5GDl8XmGyAUJOj80d9yJeUizaeRMu1LsN7XtnNLWyff2/3aULfRtA02vNdqAmhOjOo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723273446; c=relaxed/simple; bh=BX2RRXvGlkFKhS4XY9fYvxr6MZbwf9hH+dvqv87yCs8=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=Yr+OUBGDiMcw/hJA/BO45whKuKxHE5XEsG5HNgaJ9juLX0KhH6IHhsgdX4jskizD85A2z5Lq+Aa9/4ek09KMDqk3wNGvWPtn73sOb4/fn19YflOEo6ohUxSPRZ3SrjeSXkhQQwV5Juov9fadQC9/BMZ2yOAdPvc+GoE3StAwTqI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=boIx7JIi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="boIx7JIi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D772C32781; Sat, 10 Aug 2024 07:04:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1723273445; bh=BX2RRXvGlkFKhS4XY9fYvxr6MZbwf9hH+dvqv87yCs8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=boIx7JIi/GUawe8x0a3lPWZv5p3X0T1mqYUkK+sD5eAJsAUTY6a5u2dyUHS5ltBA6 bk3Mi3bvU14Sgp16HgF3Q8msLcJzWatN+PM5yBkdapPD2FvzWBPKYSI/uncO9OAZeV 39Bu6hJryH4Ks9KYk3jVAi9bAyqws/QgbUBgkB0A= Date: Sat, 10 Aug 2024 00:04:04 -0700 From: Andrew Morton To: Saurabh Singh Sengar Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, ssengar@microsoft.com, wei.liu@kernel.org Subject: Re: [PATCH] mm/vmstat: Defer the refresh_zone_stat_thresholds after all CPUs bringup Message-Id: <20240810000404.b08cb06ebbba7e0de9bb8c72@linux-foundation.org> In-Reply-To: <20240709045750.GA32083@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> References: <1720169301-21002-1-git-send-email-ssengar@linux.microsoft.com> <20240705135911.4a6e38379ae95c3fc6bbe7e2@linux-foundation.org> <20240709045750.GA32083@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 8 Jul 2024 21:57:50 -0700 Saurabh Singh Sengar wrote: > > > No NUMA = 1024*2*1*512 = 1,048,576 : Here refresh_zone_stat_thresholds > > > takes around 224 ms total for all the CPUs in the system under test. > > > 16 NUMA = 1024*2*16*512 = 16,777,216 : Here refresh_zone_stat_thresholds > > > takes around 4.5 seconds total for all the CPUs in the system under test. > > > > Did you measure the overall before-and-after times? IOW, how much of > > that 4.5s do we reclaim? > > This entire gain is accounted in over all boot processi time. Most of the Linux > kernel boot process is sequential and doesn't take advantage of SMP. Again, if you were able to measure 4.5s without the patch then you are able to measure how long this delay is with the patch. Please share that number.