Messages in this thread |  | | From | "Dave Wagner" <> | Subject | Re: [PATCH] Re: Negative scalability by removal of lock_kernel()?(Was:Strange performance behavior of 2.4.0-test9) | Date | Sat, 4 Nov 2000 20:19:28 -0800 |
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Linus Torvalds wrote: > > No. > > Please use unserialized accept() _always_, because we can fix that. > > Even 2.2.x can be fixed to do the wake-one for accept(), if required. > It's not going to be any worse than the current apache config, and > basically the less games apache plays, the better the kernel can try to > accomodate what apache _really_ wants done. When playing games, you > hide what you really want done, and suddenly kernel profiles etc end up > being completely useless, because they no longer give the data we needed > to fix the problem. > > Basically, the whole serialization crap is all about the Apache people > saying the equivalent of "the OS does a bad job on something we consider > to be incredibly important, so we do something else instead to hide it". > > And regardless of _what_ workaround Apache does, whether it is the sucky > fcntl() thing or using SysV semaphores, it's going to hide the real > issue and mean that it never gets fixed properly. > > And in the end it will result in really really bad performance. > > Instead, if apache had just done the thing it wanted to do in the first > place, the wake-one accept() semantics would have happened a hell of a > lot earlier. > > Now it's there in 2.4.x. Please use it. PLEASE PLEASE PLEASE don't play > games trying to outsmart the OS, it will just hurt Apache in the long run. >
But how would you suggest people using 2.2 configure their Apache? Will flock/fcntl or semaphores perform better (albeit "uglier") than unserialized accept()'s in 2.2. I'm willing and expecting to rebuild apache when 2.4 is released. I do not, though, want to leave performance on the table today, just so I can say that my apache binary is 2.4-ready.
Do any of the apache serialization methods (flock/fcntl/semops) have any performance improvement over unserialized accept() with Apache running on a 2.2 kernel?
Dave Wagner
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