November 2010 - Darwin-dev - lists.apple.com

Re: mac osx vs linux for high throughput network servers
by Ben Greenfield 30 Nov '10

30 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com On Nov 26, 2010, at 10:36 AM, Joel Reymont wrote: > I wonder, what OS does Apple use to run their iTunes, MobileMe, etc. services. If not Mac OSX then why? Probably a mixuture of solaris with webobjects and xserves would be my guess. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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circular log buffer
by Joel Reymont 30 Nov '10

30 Nov '10

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:from:content-type :content-transfer-encoding:subject:date:message-id:to:mime-version :x-mailer; bh=l2Hz9LSw2IciUse0k2Hx2db5sY2L6++xn8wZiy32uDE=; b=dKK6Yn+ynIS2pjTnXK0igNcvlsgjAOu+R5k63324MrdqGvudRmm+8o9PYTJPldbZBA JLHEueJ5sV3p65U7GJPSZKHCsv1zAoXyJ0UNn8EtiaY12SGXoo0v27hHNfGO/k2i3EEP bikWUHukmjRRsxhpAaevDIkU7q09qnLv4Im/c= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:content-type:content-transfer-encoding:subject:date:message-id :to:mime-version:x-mailer; b=XzPqKiQqW0yPUs2AomnZP3Y1lA/gJTNJD1p9EtAr5qCynXC6dzpGDRFKyDJEYp2H5o xr5rasv4onh7vHo7tJ3f5evaV7C+CT8ufGVybb0MwhC1Un8LkjNBXbMWHmguI1l0LeHO P9A9ERCX3Veeg6RPd8dXnayRLDdBWb8rCAODc= Does anyone have code that implements a circular log buffer? I find that using ASL with full logging increases the run time of my code from 110s to over 140s which is unacceptable. I do need to see the past few log messages on error, though. Logging to a circular buffer should give me the speed I need. I'm thinking of writing to a fixed-size buffer and dumping that log buffer as needed. Does anyone have similar code? Thanks, Joel --- http://twitter.com/wagerlabs _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Andrew Gallatin 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=simple/simple; d=cs.duke.edu; s=mail; t=1290805011; bh=S88O4Yc2s0jAU9DZFpF1xVUrslWHms7WHIXvPj30+Uo=; h=Message-ID:Date:From:MIME-Version:To:CC:Subject:References: In-Reply-To:Content-Type:Content-Transfer-Encoding; b=eot8yBIiEP0yO7OGgZ74QrQOu+Uz4x2SegBxAllFgugQPY8J7y8peBwAz6dmFTbT7 B+47pNR/yUFTpC/sZl8BHN7QA7aQN4JBDOE90qld4tfThZmjscY6WCngWxGNvV/6vn qJr3KTZkrrE2+i4URcznHuox9ZOVvlga8a5yO92g= User-agent: Thunderbird 2.0.0.24 (Macintosh/20100228) On Nov 27, 2010, at 12:26 AM, Andrew Gallatin wrote: Having done ethernet drivers for a lot of platforms (MacOSX, Linux, FreeBSD, Solaris, ESX, etc), my impression is that the linux kernel is just generally "tighter" than anything else. Eg, they've got tons of micro optimizations where they ensure data structures are aligned to cacheline boundaries, etc. I don't think anybody else has the manpower to do as good. They also don't even try to maintain source compatibility from release to release, much less a stable driver ABI. This gives them lots of freedom to optimize things. There's lots of stuff that linux has that OSX doesn't in terms of networking. AFAIK, the IOKit "workloop" based interrupt handling paradigm precludes using MSI-X & multiple receive queues, there is no DCA API for hiding cache misses, etc. I haven't looked at Lion yet (and if I had, I'd be under NDA and wouldn't be able to say..). I'm sure the whole mbuf kpi abstraction isn't doing them any favors either. I think you could probably spend a couple of man years "just" improving the network stack, and still only get close to linux. Drew _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Joel Reymont wrote: The last time I measured it, Linux blows MacOSX out of the water for UDP latency, which is what really matters for HFT (like by a factor of 2 or more). Bingo! But is this simply a matter of improving the Darwin network stack? This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Joel Reymont 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:subject:mime-version :content-type:from:in-reply-to:date:cc:content-transfer-encoding :message-id:references:to:x-mailer; bh=jOxZyQfuefUkr5Rl5injy68XrFvM1KL+t06jOiv2zyQ=; b=Vg8kEF5waa5OdOjs+/uSlNC8fkd+ru3T/hfqFL86unbTxN6cVbt+HyLvrXQ/Z++e3p Xh4EuvZqtzS3NQQYBhncHtjTDPkt7+bVSmN1dWdCWiRDBd4oBScP3q3sAUuTmsvMV0Pe h0A4MMiAYKrPG9103tZwCaIH6UMLFsFt07oPE= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer; b=xDbUALSs1BCleCwkG+dlRzEDfX5x6PxfIo3NpSv4OOUPaldOJbVq/tdOrnrZ56Oi5P bqWBEVirDT8gqrKfBfEVTHu5vi6HN2T/ElyJFkJtfW5iyU6UkBftXpNFisyED23LzGJG VCA11h/Eo9QoQgjTPWjnbnd0u3HuqK7mmMmxg= On Nov 27, 2010, at 12:26 AM, Andrew Gallatin wrote: > The last time I measured it, Linux blows MacOSX out of the water for UDP latency, which is what really matters for HFT (like by a factor of 2 or more). Bingo! But is this simply a matter of improving the Darwin network stack? --- http://twitter.com/wagerlabs _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Andrew Gallatin 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=simple/simple; d=cs.duke.edu; s=mail; t=1290788804; bh=UpSKN2jMPsfVjWJBMvWvWjnl/B0ncVrQqXs2LUPtXis=; h=Message-ID:Date:From:MIME-Version:To:CC:Subject:References: In-Reply-To:Content-Type:Content-Transfer-Encoding; b=VNcFfflpJbb+6U9bGSH/JZqMGUrBacFSwknkZIJnMQAn2b69NBF38rkl31/ATQBAn s0Fn2z8L/08m1KRywOtITvLp0H55cEm4C5hKQ8fIJ+u6qmHPgNtPnjrg9TN29C83EV Wfsng/SqSSm7aJpwrHitUd2l2OUQI3AkD9Z8WI7M= User-agent: Thunderbird 2.0.0.24 (Macintosh/20100228) The application I have in mind for Darwin is high-frequency trading. I haven't heard of it being used in this scenario, all I hear is Linux. Drew _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Joel Reymont wrote: I wonder, what OS does Apple use to run their iTunes, MobileMe, etc. services. If not Mac OSX then why? The last time I measured it, Linux blows MacOSX out of the water for UDP latency, which is what really matters for HFT (like by a factor of 2 or more). There are several vendors (including my company) that sell UDP offload solutions, which gets the UDP latency down even further (like in 3us range, wire to app). However, these solutions are generally linux or Windows focused (Myricom DBL, Solarflare, etc). This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Lawrence Sica 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com On Nov 26, 2010, at 10:36 AM, Joel Reymont wrote: > The application I have in mind for Darwin is high-frequency trading. I haven't heard of it being used in this scenario, all I hear is Linux. > > I wonder, what OS does Apple use to run their iTunes, MobileMe, etc. services. If not Mac OSX then why? > Are you going to be doing AOGs or any kind of automated trading? That is where orders per second comes into play for this sort of thing. What you need to really worry about is not the network but transactional processing on the server itself. What people on linux are using is the RT libraries, I don't know much about those under OS X really though. --Larry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Joel Reymont 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:subject:mime-version :content-type:from:in-reply-to:date:cc:content-transfer-encoding :message-id:references:to:x-mailer; bh=IK43dYWBRJC0QWdp+1heBH9P5c0C0Cy9wsp4QM+PgMk=; b=ZNZtJ/GDxWB3YnnRw5hKw7Sg/SglWiG14i9gc5k5bQW0FPGEbzWpcQJaInmTK5VAZN jD5okOQAtBP49ybFiRvY09l2Fr5IiJhh8hm+XWZLdK7nSoR4VzeFZTnU6UslSI7rdGtD PVBvbHHKe913zhRqFzSPUi0E9v8PozIt7/Djg= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer; b=i/Hil9j8GVqTtrJf9mPQu1HmDpniD9HUQ6LPSu3jU8S2DWeHnov/QyfY/IeLdT08tl C1l27e8ZthGxtBd/n6rOyWjktmun+ZYY9yEO7rmT121soZOIWF2ZnpIohpF09Gi2c/NJ lFKH9lk/Y+sqk+3nl8/+OhJ9pzRZgLzPoeXSY= The application I have in mind for Darwin is high-frequency trading. I haven't heard of it being used in this scenario, all I hear is Linux. I wonder, what OS does Apple use to run their iTunes, MobileMe, etc. services. If not Mac OSX then why? --- http://twitter.com/wagerlabs _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by François Revol 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Le 26 nov. 2010 à 16:05, Alastair Houghton a écrit : > That article is pretty poor, actually, and it doesn't show anything about the thread design since it doesn't actually test the threading system. Instead, it tests process creation (fork()-ing). On Linux, last I looked, threads were really just processes that shared address space with their parent, but on Mac OS X that is very much not the case; processes are implemented on top of Mach tasks, and have a set of Mach threads associated with them. Indeed, this doesn't seem fair. > It is also comparing G5 PowerPC Mac OS X with Linux on x86, which is just plain ridiculous. It doesn't make sense to compare except on the same hardware (and yes, Linux will run on a G5). +1 Btw, this kernel speed thing is really just for the gallery. Just like BeOS, which actually had a quite slow kernel compared to Linux, but blows it in terms of perceived reactivity. But this is about the design of the rest of the OS, threading used at the right places and so on... (and until they multithread Xorg they will still have issues) If you really want to benchmark thread context switching though here is an IBM test that used to be published on their site, that I ported to BeOS here: http://revolf.free.fr/beos/ibm_ctx_switch_article.zip You might want to add the code for OSX (though it might actually work already using pthread). But as you said, this must be run on the same machine for all OSes you test, else there is no point. François. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Alastair Houghton 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha1; c=relaxed; d=coriolis-systems.com; h= subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; s=aug07; bh=NhaCaglKbzvEnOphS3BiiJ78VFA=; b=Bxf8oUuVvZSUlEhB1LcVstQ8w6kH DWDNNLBxa08YONfCP+D9bZvuXwysLuiCnoJ1k6eb1mW6pveURdYo3hsmuRG2hC7y 5Xi+FVf5n4tYXKVgkaJ73f7uBdkgnZiZfRAAe4bpzj/OQUi0yKLVRNmxe7/NNeoB /VkTFWXt5ZF8OpI= On 26 Nov 2010, at 14:16, Matevž Markovič wrote: > You can find some info on this web page: http://www.anandtech.com/show/1702/8 (no more mysteries, G5 vs X86). > They tend to show that Linux has faster thread design. As far as I am concerned, the way OS X handels (Mach) threads is sufficient fast for about everything but the "be-the-most-responsive-web-server". That article is pretty poor, actually, and it doesn't show anything about the thread design since it doesn't actually test the threading system. Instead, it tests process creation (fork()-ing). On Linux, last I looked, threads were really just processes that shared address space with their parent, but on Mac OS X that is very much not the case; processes are implemented on top of Mach tasks, and have a set of Mach threads associated with them. It is also comparing G5 PowerPC Mac OS X with Linux on x86, which is just plain ridiculous. It doesn't make sense to compare except on the same hardware (and yes, Linux will run on a G5). Further, other things can make a huge difference; for example, I have previously had networking code run faster on a 667MHz G4 PowerBook under Mac OS X than it did on a 4GHz Pentium 4 PC running Linux. This seems surprising---I think the cause was the fact that the PowerBook had its Ethernet hardware integrated with the logic chipset, whereas the P4 machine had to send everything over PCI to its Ethernet card, and I was using small packets (deliberately). You may well find, too, that which is faster depends on whether or not the server software in question has the relevant optimisations for the platform you're testing (e.g. kqueue on Mac OS X and epoll on Linux). Kind regards, Alastair. -- http://alastairs-place.net _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: mac osx vs linux for high throughput network servers
by Matevž Markovič 26 Nov '10

26 Nov '10

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=VlXNLnSfFUuhJmWMlcpTfRdNZJQBS6iv6TeejB/ws/w=; b=cMPEewDFu8elhTrRCjvN/QGggK/feliBg4RvuLNNSkcGBVK2DS5Spokf01ygp2Lu1X NTr9qKXZ2kRRQMIavatJXhI6vFSGvLa4juNEoQqnA6r9IAzL189+3r+ilb3MDDgGrfkT PJDAox/hkkse9tOZh1cHsB8BoBnc6t5EGs/Uk= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=QHz7WQS7vD6ND9CTCFoMrnLGgxWxwRGKW5LNVomEPXrKv1e6WuH3MYXZBn3vnGvx8/ ajNeCDkE7jJGtaXaxox4yuKxXKi1ro7tBPp241r/jIvL8npjhujHgiVPQGxl7bbjzEvr RD7GUSTnLAdpLoBIBvEQVPFyEVTaaIVjgP+cI= _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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