From: "Martin Liška" <mliska@suse.cz>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: Jakub Jelinek <jakub@redhat.com>, Jeff Law <law@redhat.com>,
gcc-patches@gcc.gnu.org, Michael Matz <matz@suse.de>,
Richard Biener <richard.guenther@gmail.com>
Subject: Re: [PATCH] Deduce automatically number of cores for -flto option.
Date: Wed, 31 Jul 2019 08:37:00 -0000 [thread overview]
Message-ID: <c773e63b-889a-3f49-2390-aa9996b560c4@suse.cz> (raw)
In-Reply-To: <20190731080809.g2uerujjqvsaut74@kam.mff.cuni.cz>
On 7/31/19 10:08 AM, Jan Hubicka wrote:
> Hi,
>
>> We do not detect jobserver because of Dejagnu is not using it.
>> And yes, we default to -flto=<numthreads> in LTO tests now. That's
>> what is causing issues right now.
>
> Why the error messages are
> make[4]: *** write jobserver: Bad file descriptor. Stop.
> make[4]: *** Waiting for unfinished jobs....
> make[4]: *** write jobserver: Bad file descriptor. Stop.
> It seems to me that it is internal make from lto-wrapper trying to get
> jobserver access?
Hard to guess. Can you Jakub debug that? I don't see the error message.
>
>> Works for me.
>
> We probably also can give it a meaning controlling the default parameter
> of -flto.
> I.e. setenv GCC_LTO_PARALLELISM <numthreads/auto/jobserv>
> which we will default to in case only -flto is passed to command line.
Interesting idea, I like it, but:
- if we detect that jobserver will not work, GCC_LTO_PARALLELISM=jobserver is useless
- auto equals now to 'unset GCC_LTO_PARALLELISM'
So the only interesting value is numthreads. Then I would recommend to use
GCC_LTO_MAX_AUTO_THREADS?
>
> Make's jobserver is quite nice and easy to use. If it supported named
> pipe and there was a small library which allowed to initialize jobserver
> and connect to it, perhaps other tools needing parallelism during build
> (GCC, ninja, llvm, ...) would be able to use common protocol.
Can be a nice GSoC project for next year?
Martin
>
> Honza
>
next prev parent reply other threads:[~2019-07-31 8:21 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 8:55 [PATCH] Come up with -flto=auto option Martin Liška
2019-07-23 9:29 ` Jan Hubicka
2019-07-23 10:34 ` [PATCH] Deduce automatically number of cores for -flto option Martin Liška
2019-07-24 15:47 ` Jeff Law
2019-07-29 13:37 ` Martin Liška
2019-07-30 13:47 ` Martin Liška
2019-07-31 1:23 ` Jakub Jelinek
2019-07-31 7:24 ` Martin Liška
2019-07-31 7:40 ` Jakub Jelinek
2019-07-31 7:49 ` Jan Hubicka
2019-07-31 7:50 ` Martin Liška
2019-07-31 7:54 ` Martin Liška
2019-07-31 8:08 ` Jakub Jelinek
2019-07-31 8:21 ` Jan Hubicka
2019-07-31 8:37 ` Martin Liška [this message]
2019-07-31 9:12 ` Jakub Jelinek
2019-07-31 9:15 ` Jan Hubicka
2019-07-31 9:17 ` Jakub Jelinek
2019-07-31 9:22 ` Jan Hubicka
2019-07-31 10:02 ` Martin Liška
2019-07-31 12:02 ` Jan Hubicka
2019-07-31 15:42 ` Martin Liška
2019-08-01 13:19 ` Jakub Jelinek
2019-08-01 14:34 ` [PATCH] Properly detect working jobserver in gcc driver Martin Liška
2019-08-01 14:41 ` Jakub Jelinek
2019-08-02 6:30 ` Martin Liška
2019-08-02 7:45 ` Jakub Jelinek
2019-08-02 8:47 ` Martin Liška
2019-08-02 8:50 ` Jakub Jelinek
2019-08-02 9:04 ` Richard Biener
2019-08-02 9:08 ` Jan Hubicka
2019-08-02 9:15 ` Jan Hubicka
2019-08-02 9:19 ` Martin Liška
2019-08-02 9:55 ` Richard Biener
2019-08-05 6:41 ` Martin Liška
2019-08-09 8:14 ` Martin Liška
2019-08-09 8:22 ` Richard Biener
2019-08-09 12:51 ` Martin Liška
2019-08-09 13:56 ` Martin Liška
2019-08-12 15:18 ` Jeff Law
2019-07-23 13:13 ` [PATCH] Come up with -flto=auto option Jeff Law
2019-07-23 13:22 ` Richard Biener
2019-07-23 13:57 ` Michael Matz
2019-07-23 14:00 ` Jeff Law
2019-07-23 14:27 ` Martin Liška
2019-07-23 22:56 ` Jeff Law
2019-07-24 6:59 ` Martin Liška
2019-07-24 15:16 ` Jeff Law
2019-07-23 22:32 ` Allan Sandfeld Jensen
2019-07-24 6:47 ` Martin Liška
2019-07-24 7:12 ` Allan Sandfeld Jensen
2019-07-24 7:15 ` Martin Liška
2019-07-24 11:09 ` Nathan Sidwell
2019-07-24 15:46 ` Jeff Law
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