From: Jonathan Tan <jonathantanmy@google.com>
To: Stefan Beller <sbeller@google.com>
Cc: "git@vger.kernel.org" <git@vger.kernel.org>,
Jonathan Nieder <jrnieder@gmail.com>,
Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2] fetch-pack: grow stateless RPC windows exponentially
Date: Tue, 19 Jul 2016 12:03:24 -0700 [thread overview]
Message-ID: <CAGf8dgL3t7uX7yAux0xc2QMJJdmnM0262Quj4o6gDehwA+4JqQ@mail.gmail.com> (raw)
In-Reply-To: <CAGZ79kY+2PYx9oz9tvi0zG-oE6qS-Za7D3ocY1XtqcSsDchz0Q@mail.gmail.com>
On Tue, Jul 19, 2016 at 9:46 AM, Stefan Beller <sbeller@google.com> wrote:
> Care to elaborate on why you choose 11/10 as growth factor?
>
> (As someone who has a tick in micro optimizing:
> 9/8 is roughly the same exponent, but the division
> by 8 is easier as it is just a shift by 3. Similar 17/16)
I don't have a specific reason for 11/10 as opposed to, say, 9/8 - I
think that the time taken to execute this line is negligible compared
to what's done in the calling code, but I'll change it to 9/8 if there
is another reason for me to send another patch.
> I guess one design criterion was 10 being a round number?
> Does it make sense to experiment with the factor at all?
> Digging into that, LARGE_FLUSH originates from 6afca450c3f,
> (2011-03-20, fetch-pack: progressively use larger handshake windows),
> and before we only had a linear growth.
>
> So I guess what I do not understand is why we need to slow down the
> exponential growth at all?
The current code has an exponential (a' = a * 2) then a linear (a' = a
+ 1024) growth. I'm not slowing down the exponential growth - that
part is retained. I'm replacing the linear growth with another
conservative exponential growth (a' = a * 11 / 10).
next prev parent reply other threads:[~2016-07-19 19:03 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-18 18:36 [PATCH] fetch-pack: grow stateless RPC windows exponentially Jonathan Tan
2016-07-18 18:55 ` Jonathan Nieder
2016-07-18 19:10 ` Junio C Hamano
2016-07-18 19:16 ` Jonathan Tan
2016-07-18 19:31 ` Jonathan Nieder
2016-07-18 20:00 ` Junio C Hamano
2016-07-18 21:05 ` Jonathan Tan
2016-07-18 21:36 ` Junio C Hamano
2016-07-18 22:21 ` [PATCH v2] " Jonathan Tan
2016-07-18 22:40 ` Jonathan Nieder
2016-07-19 16:46 ` Stefan Beller
2016-07-19 19:03 ` Jonathan Tan [this message]
2016-07-19 19:17 ` Stefan Beller
2016-07-19 19:23 ` Junio C Hamano
2016-07-19 19:53 ` Jonathan Nieder
2016-07-19 20:20 ` Junio C Hamano
2016-07-20 13:40 ` Jeff King
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