From: Eric Biggers Subject: Re: [PATCH v7 0/5] Update LZ4 compressor module Date: Wed, 8 Feb 2017 16:24:36 -0800 Message-ID: <20170209002436.GA103792@gmail.com> References: <1482259992-16680-1-git-send-email-4sschmid@informatik.uni-hamburg.de> <1486321748-19085-1-git-send-email-4sschmid@informatik.uni-hamburg.de> <20170208233121.GA16728@bbox> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Sven Schmidt <4sschmid@informatik.uni-hamburg.de>, akpm@linux-foundation.org, bongkyu.kim@lge.com, rsalvaterra@gmail.com, sergey.senozhatsky@gmail.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, herbert@gondor.apana.org.au, davem@davemloft.net, linux-crypto@vger.kernel.org, anton@enomsg.org, ccross@android.com, keescook@chromium.org, tony.luck@intel.com To: Minchan Kim Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:33781 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752002AbdBIAYj (ORCPT ); Wed, 8 Feb 2017 19:24:39 -0500 Content-Disposition: inline In-Reply-To: <20170208233121.GA16728@bbox> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Thu, Feb 09, 2017 at 08:31:21AM +0900, Minchan Kim wrote: > > Today, I did zram-lz4 performance test with fio in current mmotm and > found it makes regression about 20%. > This may or may not be the cause of the specific regression you're observing, but I just noticed that the proposed patch drops a lot of FORCEINLINE annotations from upstream LZ4. The FORCEINLINE's are there for a reason, especially for the main decompression and compression functions which are basically "templates" that take in different sets of constant parameters, and should be left in. We should #define FORCEINLINE to __always_inline somewhere, or just do a s/FORCEINLINE/__always_inline/g. Note that the upstream LZ4 code is very carefully optimized, so we should not, in general, be changing things like when functions are force-inlined, what the hash table size is, etc. [Also, for some reason linux-crypto is apparently still not receiving patch 1/5 in the series. It's missing from the linux-crypto archive at http://www.spinics.net/lists/linux-crypto/, so it's not just me.] Thanks! Eric