Re: When can we make Squid using multi-CPU?
On Sun, 2009-01-04 at 10:03 +0800, ShuXin Zheng wrote: Hi, Squid current can only use one CPU, but multi-CPU hardware machines are so popular. These are so greatly wastely. How can we use the multi-CPU? Can we separate some parallel sections which are CPU wasting to run on different CPU? OMP(http://openmp.org/wp/) gives us some thinking about using multi-CPU, so can we use these technology in Squid? SMP support has been earmarked for Squid v3.2 but there is currently not enough resources to make it happen (AFAICT) so it may have to wait until v3.3 or later. FWIW, I think that multi-core scalability in many environments would not require another Squid rewrite, especially if initial support does not have to do better than running multiple Squids. You can monitor this project progress at http://wiki.squid-cache.org/Features/SmpScale Thank you, Alex.
Re: When can we make Squid using multi-CPU?
2009/1/8 Alex Rousskov rouss...@measurement-factory.com: SMP support has been earmarked for Squid v3.2 but there is currently not enough resources to make it happen (AFAICT) so it may have to wait until v3.3 or later. FWIW, I think that multi-core scalability in many environments would not require another Squid rewrite, especially if initial support does not have to do better than running multiple Squids. Well, people are already doing that where its suitable. Whats really missing for those sorts of setups is a simple(!) storage-only backend and some smarts in Squid to be able to push and pull stuff out of a shared storage backend, rather than relaying through it. The trouble, as I've found here, is if you're trying to aggregate a bunch of forward proxy squid instances on one box through one backend squid instance - all of a sudden you end up with lots of RAM wastage and things die at high loads with all the duplicate data floating around in socket buffers. :/ Adrian
Re: When can we make Squid using multi-CPU?
I've been looking into what would be needed to thread squid as part of my cacheboy squid-2 fork. Basically, I've been working on breaking out a bunch of the core code into libraries, which I can then check and verify are thread-safe. I can then use these bits in threaded code. My first goal was probably to break out the ACL and internal URL rewriter code into threads, but the current use of the callback data setup in Squid makes passing cbdata pointers into other threads quite uhm, tricky. The basic problem is that although a given chunk of memory backing a cbdata pointer will remain valid for as long as the reference exists, the -data itself- may not be valid at any point. So if thread A creates a cbdata pointer and passes it into thread B to do something (say an ACL lookup), there's no way (at the moment) for thread B to guarantee at any/all points during its execution that the data in B will stay valid without a whole lot of pissing around with locking, which I'd absolutely like to avoid doing in a high performance network application even the apparent wonderful performance current hardware has w/ lots of locking. :) So for the time being, I'm looking at what would be needed for a basic inter-thread batch event/callback message queue, sort of like AsyncCalls in squid-3 but minus 100% of the legacy cruft; and then I'll see what kind of tasks can be pushed out to the threads. Hopefully a bunch of stuff can be easily pushed out to threads with a minimum amount of effort, such as some/all of the ACL lookups, some URL rewriting, some GZIP and other kind of basic content mainpulation, and the freakishly simple (comparitively) server-side HTTP code (src/http.c). But doing that requires making sure a bunch of the low level code is suitably re-enterant/thread-safe/etc, and this includes a -lot- of stuff (lib/, debug, logging, memory allocation, some statistics gathering, chunks of the HTTP parsing and packing routines, the packer routines, membufs, etc.) Thankfully (in Cacheboy) I've broken out almost all of the needed stuff into top-level libraries which can be independently audited for thread-happiness. There's just some loose ends which need tidying up. For example, almost all of the code in libhttp/ in cacheboy (ie, basic http header and header entry stuff, parsing, range request headers, cc, headers, etc) are thread-safe, but the functions -they- call (such as the base64 functions) use static buffers which may or may not be thread-safe. Stuff which calls the legacy non-safe inet_* routines, or perhaps the non thread-safe strtok() and other string.h functions, all need to be fixed. Threading the rest of it would take a lot, -lot- more time. A thread-aware storage backend (disk, memory, store index) is definitely an integral part of making a threaded Squid, and a whole lot more code modularity and reorganisation would have to take place for that to occur. Want to help? :) Adrian 2009/1/4 ShuXin Zheng zhengshu...@gmail.com: I've ever do this to run multi-squid on one machine which can use multi-CPU, but can't share the same store-fs, and must configure multi-IP on the same machine. Can we rewrite squid as follow: thread0(client side, no block, can accept many connections) thread1 ..threadn(n=CPU number) | | v v access check access check | | v v http header parse http header parse | | v v acl filter acl filter | | v v check local cache check local cache | | v v --- | neighbor| ||-ufs webserver--|--- forward - |store fs |-aufs | | |-coss --- |(thread0) |(thread1) .. v v ... 2009/1/4 anest...@cisdi.com: I've found the best way is to run multiple copies of squid on a single machine, and use LVS to load balance between the squid processes. -- Joe Quoting Adrian Chadd adr...@squid-cache.org: when someone decides to either help code it up, or donate towards the effort. adrian 2009/1/3 ShuXin Zheng zhengshu...@gmail.com: Hi, Squid current can only use one CPU, but multi-CPU hardware machines are so popular. These are so greatly wastely. How can we use the multi-CPU? Can we separate some parallel sections which are CPU wasting to run on different CPU? OMP(http://openmp.org/wp/) gives us some thinking about using multi-CPU, so can we use these technology in Squid? Thanks
Re: When can we make Squid using multi-CPU?
I've ever do this to run multi-squid on one machine which can use multi-CPU, but can't share the same store-fs, and must configure multi-IP on the same machine. Can we rewrite squid as follow: thread0(client side, no block, can accept many connections) thread1 ...threadn(n=CPU number) | | v v access check access check | | v v http header parse http header parse | | v v acl filter acl filter | | v v check local cache check local cache | | v v --- | neighbor| ||-ufs webserver--|--- forward - |store fs |-aufs | | |-coss --- |(thread0) |(thread1) .. v v ... 2009/1/4 anest...@cisdi.com: I've found the best way is to run multiple copies of squid on a single machine, and use LVS to load balance between the squid processes. -- Joe Quoting Adrian Chadd adr...@squid-cache.org: when someone decides to either help code it up, or donate towards the effort. adrian 2009/1/3 ShuXin Zheng zhengshu...@gmail.com: Hi, Squid current can only use one CPU, but multi-CPU hardware machines are so popular. These are so greatly wastely. How can we use the multi-CPU? Can we separate some parallel sections which are CPU wasting to run on different CPU? OMP(http://openmp.org/wp/) gives us some thinking about using multi-CPU, so can we use these technology in Squid? Thanks -- zsxxsz -- zsxxsz
When can we make Squid using multi-CPU?
Hi, Squid current can only use one CPU, but multi-CPU hardware machines are so popular. These are so greatly wastely. How can we use the multi-CPU? Can we separate some parallel sections which are CPU wasting to run on different CPU? OMP(http://openmp.org/wp/) gives us some thinking about using multi-CPU, so can we use these technology in Squid? Thanks -- zsxxsz
Re: When can we make Squid using multi-CPU?
when someone decides to either help code it up, or donate towards the effort. adrian 2009/1/3 ShuXin Zheng zhengshu...@gmail.com: Hi, Squid current can only use one CPU, but multi-CPU hardware machines are so popular. These are so greatly wastely. How can we use the multi-CPU? Can we separate some parallel sections which are CPU wasting to run on different CPU? OMP(http://openmp.org/wp/) gives us some thinking about using multi-CPU, so can we use these technology in Squid? Thanks -- zsxxsz
