Re: [hybi] Background info: Properties of sendfile()
Jamie Lokier <jamie@shareable.org> Fri, 06 August 2010 18:01 UTC
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Date: Fri, 06 Aug 2010 19:01:26 +0100
From: Jamie Lokier <jamie@shareable.org>
To: Willy Tarreau <w@1wt.eu>
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References: <F8E2F702-9F74-4316-B3B2-D5A731409ABF@apple.com> <4C5B2029.90403@gmx.de> <AANLkTim1WeCRfcPxXUNQcVhb4+t_TtDQDv2bXaxOQ=bk@mail.gmail.com> <01098AD0-FBF4-4A61-B565-947C95722BAA@apple.com> <AANLkTi=qQSND5BvUP5+P=wJ7E8SG6NncGZH8U8+VYwZ0@mail.gmail.com> <20100806004907.GF27827@shareable.org> <C0FC87B7-C51C-4B36-BC16-DBDB0B00A20F@gbiv.com> <20100806012845.GI27827@shareable.org> <AANLkTimuvuj87qwQi_1Gjg47-gGrCsDCQ5TDd5zvOw1N@mail.gmail.com> <20100806062928.GF20057@1wt.eu>
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Cc: "Roy T. Fielding" <fielding@gbiv.com>, "hybi@ietf.org" <hybi@ietf.org>
Subject: Re: [hybi] Background info: Properties of sendfile()
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Willy Tarreau wrote: > On Thu, Aug 05, 2010 at 06:47:48PM -0700, Roberto Peon wrote: > > Thus my statement of "theoretical" benefits. > > I've not seen the benefits of either splice or sendfile yet. > > At least I've seen it. Haproxy happily forwards traffic at 10 Gbps > with only 25% of one CPU core on a 2.66 GHz Core2Duo using splice(). > And some file sharing sites make a big use of it ! Without splice, > it hardly achieves 10 Gbps at 100% CPU. > > Anyway, it's unclear to me why we would need to send large amounts > of data over WebSockets. File serving could well be performed by > the web server itself. Some examples: - You've got a web app which carries user-generated short messages, that should not be fragile when a user decides to send a long one. For example an IM client, when a user tries cutting-and-pasting 20 pages of text (70kB) into an entry, there is no good reason for that to crash the app. (Certainly not just because of a WebSocket limit being hit.) Yes, users occasionally do this sort of thing. - Dynamic HTML updates sent from the server (expect lots of this in web apps). Live wiki editing, shared documents etc. They send HTML fragment update messages to update the browser. Normally they'll be small, but under various circumstances (including temporary network outage so the user queues up a lots of deltas), an HTML update may occasionally be larger than usual. It should just work, without invoking rarely-used code paths. - The old IM again, with inline smileys and avatars. If you need to get the latency down you may encode these small images into an update message. They're small, but vary in size and may occasionally exceed some arbitrary small limit, if there is one. In a nutshell: The WS API should not hold surprises, cause unnecessarily fragility in the apps using it, or require apps to have exceptional code paths, where that's easy to avoid. -- Jamie
- Re: [hybi] hum #3: Message Jamie Lokier
- [hybi] hum #3: Message Salvatore Loreto
- Re: [hybi] hum #3: Message Ian Hickson
- Re: [hybi] hum #3: Message John Tamplin
- Re: [hybi] hum #3: Message Douglas Otis
- Re: [hybi] hum #3: Message Maciej Stachowiak
- Re: [hybi] hum #3: Message Dave Cridland
- Re: [hybi] hum #3: Message Ian Hickson
- Re: [hybi] hum #3: Message Julian Reschke
- Re: [hybi] hum #3: Message John Tamplin
- Re: [hybi] hum #3: Message Jack Moffitt
- Re: [hybi] hum #3: Message Bjoern Hoehrmann
- Re: [hybi] hum #3: Message Willy Tarreau
- Re: [hybi] hum #3: Message Bjoern Hoehrmann
- Re: [hybi] hum #3: Message Maciej Stachowiak
- Re: [hybi] hum #3: Message Julian Reschke
- Re: [hybi] hum #3: Message Roberto Peon
- Re: [hybi] hum #3: Message Maciej Stachowiak
- Re: [hybi] hum #3: Message Jack Moffitt
- Re: [hybi] hum #3: Message Willy Tarreau
- Re: [hybi] hum #3: Message Maciej Stachowiak
- Re: [hybi] hum #3: Message Maciej Stachowiak
- Re: [hybi] hum #3: Message Dave Cridland
- Re: [hybi] hum #3: Message Maciej Stachowiak
- Re: [hybi] hum #3: Message Dave Cridland
- Re: [hybi] hum #3: Message Greg Wilkins
- Re: [hybi] hum #3: Message Dave Cridland
- Re: [hybi] hum #3: Message Jack Moffitt
- Re: [hybi] hum #3: Message Ian Fette (イアンフェッティ)
- Re: [hybi] hum #3: Message Ian Fette (イアンフェッティ)
- [hybi] Background info: Properties of sendfile() Jamie Lokier
- Re: [hybi] hum #3: Message Jamie Lokier
- Re: [hybi] Background info: Properties of sendfil… Roy T. Fielding
- Re: [hybi] Background info: Properties of sendfil… Jamie Lokier
- Re: [hybi] Background info: Properties of sendfil… Greg Wilkins
- Re: [hybi] Background info: Properties of sendfil… Roberto Peon
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] Background info: Properties of sendfil… Jamie Lokier
- Re: [hybi] Background info: Properties of sendfil… Greg Wilkins
- Re: [hybi] Background info: Properties of sendfil… Willy Tarreau
- Re: [hybi] Background info: Properties of sendfil… Maciej Stachowiak
- Re: [hybi] Background info: Properties of sendfil… Willy Tarreau
- Re: [hybi] hum #3: Message Pieter Hintjens
- Re: [hybi] hum #3: Message Arman Djusupov
- Re: [hybi] hum #3: Message Pieter Hintjens
- Re: [hybi] hum #3: Message Julian Reschke
- Re: [hybi] hum #3: Message Arman Djusupov
- Re: [hybi] Background info: Properties of sendfil… Jack Moffitt
- Re: [hybi] hum #3: Message John Tamplin
- Re: [hybi] hum #3: Message Arman Djusupov
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] hum #3: Message Patrick McManus
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] hum #3: Message Patrick McManus
- Re: [hybi] Background info: Properties of sendfil… Roberto Peon
- Re: [hybi] Background info: Properties of sendfil… Jamie Lokier
- Re: [hybi] hum #3: Message Dave Cridland
- Re: [hybi] hum #3: Message Dave Cridland
- Re: [hybi] hum #3: Message Douglas Otis
- [hybi] Impact of mandatory chunking (was Re: Back… Maciej Stachowiak
- Re: [hybi] Impact of mandatory chunking (was Re: … Jack Moffitt
- Re: [hybi] hum #3: Message Pieter Hintjens
- Re: [hybi] Impact of mandatory chunking (was Re: … Maciej Stachowiak
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] hum #3: Message Willy Tarreau
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] hum #3: Message Roberto Peon
- Re: [hybi] hum #3: Message Willy Tarreau
- Re: [hybi] hum #3: Message Scott Ferguson
- Re: [hybi] hum #3: Message Pieter Hintjens
- Re: [hybi] hum #3: Message Greg Wilkins
- Re: [hybi] hum #3: Message Pieter Hintjens
- Re: [hybi] hum #3: Message Martin Sustrik
- Re: [hybi] hum(s) followup Maciej Stachowiak
- [hybi] hum(s) followup Salvatore Loreto
- Re: [hybi] hum(s) followup Pieter Hintjens
- Re: [hybi] hum(s) followup Salvatore Loreto