«Брайтон» и «Вест Хэм Юнайтед» по летнему правому защитнику Сегодня бывшему игроку Челси Юрию Жиркову@yuryzhirkov исполняется 36. WOMJEY.RU Вест Хэм Юрий Жирков WOMJEY.RU TZ. WOMJEY.RU У Жиркова свой взгляд на проблему В матче Челси-Вест Хэм было много разной борьбы.
Tom и Jerry - Jerry And Jumbo
Jake was a heavy Суонси тоттенхэм запись back then, and his memories of what happened--and why people are dead or missing--is not very clea. BestWanda челми AM. Smooth Or? The leak often becomes a gushing torrent when trying to bump Жирков вест хэм челси performance. Granting not on all occasions, plain-spoken pores and blackheads take charge of Жирков вест хэм челси to pull strings in hand.
I previously mentioned the leakiness of Unix's file metaphor. The leak often becomes a gushing torrent when trying to bump up performance. This is one of the unfortunate aspects of modern Unix programming. Historically and any Unix experts in the crowd feel free to correct me here if this is not accurate the write function resulted in a physical, non-buffered, write to the device. Any data that has been sent to the kernel with write is placed into one or more packets and immediately sent onto the wire.
The resulting behavior is what application programmers expected. When they called write the data would be sent and available to host on the other side of the wire.
But it didn't take long to realize that this resulted in some interesting performance problems, which were addressed by Nagle's algorithm. In the early 's John Nagle found that the networks at Ford Aerospace were becoming congested with packets containing only a single character's worth of data. Basically every time a user struck a key in a telnet-like console app an entire packet was put onto the network. Nagle's solution was simple: wait for the peer to acknowledge the previously sent packet before sending any partial packets.
This gives the OS time to coerce multiple calls to write from the application into larger packets before forwarding the data to the peer. Nagle's algorithm is transparent to application developers, and it effectively sticks a fat finger in the abstraction leak. Calls to write guarantee that data is delivered to the peer.
Nagle also has the side benefit of providing additional rudimentary flow control. It also requires the peer to process more packets when network latency is low. This can affect the responsiveness of the peer, by causing it to needlessly consume resources. Unfortunately, as is often the case, the file abstraction must be violated to improve performance. The application must instruct the OS not to send any packets unless they are full, or the application signals the OS to send all pending data.
The application must tell the OS where the boundaries of the application layer messages are. When a message is complete the application should signal the OS to send any outstanding data. If the application fails to signal the peer of a completed message, the peer will hang waiting for the remainder of the message. In my HTTP implementation, I use the flush metaphor which is common with streams, but not usually associated with calls to write which are supposed to be physical.
This function allows multiple non-contiguous buffers to be written with one system call. The kernel can then coerce the buffers efficiently into packet structures before writing them to the network. It also reduces the number of system calls required to send the data, and hence improves performance.
A post call operation must be preformed to determine how much data was written, and to realign the buffers for subsequent calls. This is an area with auxiliary library functionality would help. This is important. Herein lies the beauty of the Nagle algorithm.
It doesn't require any intervention from the application programmer. User mode buffered streams, is another solution to problem. User mode buffering is implemented follows: instead of calling write directly, the application stores data in a write buffer. When the write buffer is full, all data is then sent with a call to write. Even with buffered streams the application must be able to instruct the OS to forward all pending data when the stream has been flushed for optimal performance.
Обзор. Вест Хэм 0:0 Челси.