diff --git a/doc/fluid/design/dist_train/async_update.md b/doc/fluid/design/dist_train/async_update.md index 344a44bde8..0318ef33c2 100644 --- a/doc/fluid/design/dist_train/async_update.md +++ b/doc/fluid/design/dist_train/async_update.md @@ -28,10 +28,10 @@ the parameter `w1` as an example to introduce the steps: 1. For each gradient variables, they may distribute on different GPU card and aggregate them while they are all calculated. 1. Split the gradient variable into multiple blocks according to the number of PServer -instances and then sent them. +instances and then send them. 1. PServer would run an `Optimize Block` using a specified optimize algorithm to update the specified parameter. -1. The trainer will fetch the parameter before running forward Op depends on the specified +1. The trainer will fetch the parameter before running forward Op which depends on the specified parameter. 1. Broadcast the received variable into multiple GPU cards and continue to run the next mini-batch. @@ -44,7 +44,7 @@ send the gradient variables to the multiple PServer instances. - Schedule `FetchVars` operator to fetch the latest parameter from PServer before running the forward ops. - There could be a large number of gradient variables to be sent, so we need to use another -thread pool(IO Threadpool) which a number of the schedulable threads is larger than the +thread pool(IO Threadpool) whose a number of the schedulable threads is larger than the computing thread pool to avoid competitive the thread resources with computing. ### Parameter Server @@ -52,7 +52,7 @@ computing thread pool to avoid competitive the thread resources with computing. - There should be multiple trainer instances want to optimize the same parameter at -the same time, to avoid the pollution, we need one `BlockingQueue` for each gradient +the same time, to avoid the racing, we need one `BlockingQueue` for each gradient variable to process them one by one. - We need a `Map` structure to map a gradient variable name to the `OptimizeBlock` which can optimize the respective parameter. diff --git a/doc/fluid/design/dist_train/src/async_pserver.graffle b/doc/fluid/design/dist_train/src/async_pserver.graffle index ea6dcfa2a9..d230161177 100644 Binary files a/doc/fluid/design/dist_train/src/async_pserver.graffle and b/doc/fluid/design/dist_train/src/async_pserver.graffle differ diff --git a/doc/fluid/design/dist_train/src/async_pserver.png b/doc/fluid/design/dist_train/src/async_pserver.png index a3e18126c3..7d900b0c0e 100644 Binary files a/doc/fluid/design/dist_train/src/async_pserver.png and b/doc/fluid/design/dist_train/src/async_pserver.png differ