From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 20EC129B795 for ; Wed, 11 Mar 2026 05:22:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773206528; cv=none; b=G37cVJMoNF+9vndYtMtgGYGbCVVbOiBdVjM1npdSJml1LrVN5KpS6OkcQpJQh2KisDv+gfOxFBo5RVLb1VUix9Pha+RqUjdF2oSBJ8jXpQwp87Tp0J+9/pzxorbRnRqnPVrAWR2BdRjP/ODa5Hjqd3UfX1EEZh7K9phJhW2KdU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773206528; c=relaxed/simple; bh=zan1LPmq6HbmulMzgA9gW+UUtyY5DbZLNRaN3yrnRdY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ia/Sm2jH0NJSW3oUAi3lPHRQJTxM2F4NfkG/USCt9cqpmy3eUDfJSCa/jpWCnhdIRyUWEyXiAjWmsZsuuDrQC2kiyB4XKlCz6lcoRm+bSOc8e5ZNPJCVil9vg0ZKXL5qmIp6av/euBrwHcI8zzvKQFzwcJxgqQcjnZFr3xUEYnU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=n3X508/B; arc=none smtp.client-ip=209.85.210.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="n3X508/B" Received: by mail-pf1-f178.google.com with SMTP id d2e1a72fcca58-829ac8d56c5so4264460b3a.3 for ; Tue, 10 Mar 2026 22:22:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1773206526; x=1773811326; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=NorOqui97Uy+vQC59x0dyKRHlJOJ9bIHMLqnBZs2Jos=; b=n3X508/BMyN/vIirFR8yZFoGj3FhFqg9MViZu+NnjCN8k+wvwY97NaHgHKUXza74KB Qd/jpaflMauHqHqMVHX2maMIecDAP+jhkuVBgemAAc8zNbLegdp/r43JMr0AfxbiKydj cPEM61axCxeKkvg6VUd2a4FWPUHr1Zq6mKa38= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773206526; x=1773811326; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=NorOqui97Uy+vQC59x0dyKRHlJOJ9bIHMLqnBZs2Jos=; b=BrVveHqyV+goEZD5+j+TdU0ds9plYew1SqLpNv3M4mQTNlX2klyWlh+1O9pss53aGJ 6PoHfW81xNS9aL9hXJ9mPEj1W04IO+u62NbYsuGOWbWxDP9oal4G+TMFonTrSalQxJ+2 JSJPjyG+SiAO4nx2pHdTtvrUY6iFZH42El7mi2yCO4+NdzptxYOS8g1FXOY+JhhnyRPt QlUY2yHdqyzjc+WxtvnFPLFmdqbJ+eWTNDIwxyxKaPv9fEVcSfROwc1zVasQO6CK3b7M HF16z67L/E6NG4A95XcYBxyqXlZmxK0ItvOdRrAh4C0ZnhjKrzoMfCuGZdedTfA3gHb/ usBw== X-Forwarded-Encrypted: i=1; AJvYcCU1F0StVQVtvbJnQ395YPEHuGW4HsQ13wUhyCZa8vVkJ8n3TNEAqyuVtxBdw+LOeZojuCr23aqi2qURDMo=@vger.kernel.org X-Gm-Message-State: AOJu0Yy0AuL4DAO7R+a0yQZ//iP8UBy5sAXssDdMOos7GNdYBc+nISUE Szikgb5qQMB7JBlDlE2DrsGyLGl+8UGhNLYsBaKdLbyLtqJiJizMik4TUt6qOvvxXA== X-Gm-Gg: ATEYQzyNjM656e4Qn8B51fzqIHfgFo5lBDoTP5ErrOycZ/Ngcf2IfHcgW7VvC9teBph riek1pZVsl8HHDh5L1pq1j4t+BXOStK8Bq8InG3lqhswfNI4OAY9rx4hPisf/FkJYASzsPTyhA0 UDtIaoS3HTPNJn5f9ipbgBMoTLD/qVNyHU7WN60mgwwN1wFtiF0EPTJurOb0nWZ3sjnwJDe9Ev5 sTlKSx/vUS5P+shLi0mPOmlsLgWi+qhOL/+D+zV754Ht5qaCm0RuaYLzVKUlLqlXc1aErfSjOGc Im0+QrL+JRMjmaRvyaPSUladVWgMwYyOGFM+VhomvWpWtx+ZeQTT9qn/VYw/0gzesrLCf1nvBQY Q2wKP1RnERMydmPyAYTU84iwF2qG3KR7zle04DdPVA0nUMU+HhI0/PY6AYyXOt6gaz9juYWiYTx w1h9kxVux1d+798jhVzGyf3sNNrebAMtHJY06iA/0j60vVlT46TW9p+ZSHcU0JAYTLAhZC1IwBS g== X-Received: by 2002:a05:6a00:430a:b0:829:6f82:5953 with SMTP id d2e1a72fcca58-829f6eee0damr1238945b3a.5.1773206526485; Tue, 10 Mar 2026 22:22:06 -0700 (PDT) Received: from google.com ([2a00:79e0:2031:6:93a4:8281:fe98:426a]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-829f6dc0c9bsm978368b3a.5.2026.03.10.22.22.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Mar 2026 22:22:05 -0700 (PDT) Date: Wed, 11 Mar 2026 14:22:02 +0900 From: Sergey Senozhatsky To: gao xu Cc: Sergey Senozhatsky , Minchan Kim , Jens Axboe , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , "surenb@google.com" , zhouxiaolong Subject: Re: zram: Optimize LZ4 dictionary compression performance Message-ID: References: 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-Disposition: inline In-Reply-To: On (26/03/11 04:00), gao xu wrote: > > On (26/03/10 02:54), gao xu wrote: > > > + memcpy(zctx->cstrm, &drv->base_cstream, > > > + sizeof(*zctx->cstrm)); > > > > Do we need to do this memcpy() every time? > memcpy is a replacement for LZ4_loadDict. LZ4_loadDict updates > the LZ4 hash table using the dictionary. Furthermore, LZ4 also > updates its hash table with the results of the previous compression. > Therefore, to ensure the compression dictionary remains effective, we > would need to reset the hash table every time, which would involve > executing memcpy() or LZ4_loadDict() OK, I see. (I assume you tested and verified that.)