From: Jens Axboe <axboe@kernel.dk>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Recent slowdown in single object builds
Date: Sun, 17 Nov 2019 19:34:42 -0700 [thread overview]
Message-ID: <38007c4c-45ff-d00e-05c5-948a2df783df@kernel.dk> (raw)
In-Reply-To: <CAK7LNARUzJx==c1gh33obme21JiRR1CrKELkGpmPJQANx0LqSw@mail.gmail.com>
On 11/17/19 5:40 PM, Masahiro Yamada wrote:
> On Sun, Nov 17, 2019 at 1:57 AM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> On 11/16/19 12:17 AM, Masahiro Yamada wrote:
>>> On Sat, Nov 16, 2019 at 8:10 AM Jens Axboe <axboe@kernel.dk> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I've noticed that current -git is a lot slower at doing single object
>>>> builds than earlier kernels. Here's an example, building the exact same
>>>> file on 5.2 and -git:
>>>>
>>>> $ time make fs/io_uring.o
>>>> real 0m5.953s
>>>> user 0m5.402s
>>>> sys 0m0.649s
>>>>
>>>> vs 5.2 based (with all the backports, identical file):
>>>>
>>>> $ time make fs/io_uring.o
>>>> real 0m3.218s
>>>> user 0m2.968s
>>>> sys 0m0.520s
>>>>
>>>> Any idea what's going on here? It's almost twice as slow, which is
>>>> problematic...
>
>
> BTW, I am using a cheap machine based on Intel Core i7-6700K.
> I can build fs/io_uring.o (based on x86_64_defconfig) much faster.
>
>
> The slowdown (1.990 sec -> 2.861 sec) is not terrible for me.
For those of us that do single object builds all the time the slowdown
is pretty damn terrible. Granted that your 44% slowdown isn't as bad as
my 85% slowdown, but it's still a MASSIVE slowdown.
--
Jens Axboe
prev parent reply other threads:[~2019-11-18 2:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 23:10 Recent slowdown in single object builds Jens Axboe
2019-11-16 7:17 ` Masahiro Yamada
2019-11-16 16:57 ` Jens Axboe
2019-11-18 0:40 ` Masahiro Yamada
2019-11-18 2:34 ` Jens Axboe [this message]
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