From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Korsgaard Date: Sun, 27 Jan 2019 23:06:14 +0100 Subject: [Buildroot] [PATCH 1/1] fs/common.mk: enable multithreaded xz compression In-Reply-To: <20190126150622.23c7375e@windsurf> (Thomas Petazzoni's message of "Sat, 26 Jan 2019 15:06:22 +0100") References: <1548036475-25449-1-git-send-email-james.hilliard1@gmail.com> <871s55ykoj.fsf@dell.be.48ers.dk> <20190126150622.23c7375e@windsurf> Message-ID: <87a7jln4bt.fsf@dell.be.48ers.dk> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net >>>>> "Thomas" == Thomas Petazzoni writes: > Hello, > On Mon, 21 Jan 2019 18:39:24 +0100, Peter Korsgaard wrote: >> > I thought it was using the version compiled by buildroot. >> > Isn't that what host-xz is being used for? >> >> Yes, correct. Do you know if the -T 0 option generates identical output >> as -T 1? Otherwise we may want to disable it for reproducible builds. > Does it matter than the output of -T 0 and -T 1 are identical ? It would cause an extra change in output between buildroot versions using -T 0 and ones using -T 1 - But OK, probably that isn't really important given all the other changes. What I really meant was if the -T 1 option affected the output format, and if so, if the difference involved any tradeoff (E.G. perhaps -T 1 compresses slightly worse than -T 0) and if repeated runs with -T 1 would generate the same output (on same machine or on another machine with different number of threads). > What matters for BR2_REPRODUCIBLE=y is if the same input, with -T 0, > always provide the exact identical output. With the new patch that only enables -T 1 for !reproducible builds, that is correct. -- Bye, Peter Korsgaard