我遇到一个问题,在
keras::unserialize_model()
doParallel
循环中调用 foreach
时 R 崩溃。
我必须清理这段代码,所以希望我不会乱搞任何东西。而且我不是 R 开发人员;我正在尝试将其他人编写的一些 R 代码移至生产运行时环境中。
如果我运行此代码,它会阻止加载并且不会崩溃:
#unserialize models locally
my_model1 <- keras::unserialize_model(ser_model1)
my_model2 <- keras::unserialize_model(ser_model2)
my_model3 <- keras::unserialize_model(ser_model3)
my_model4 <- keras::unserialize_model(ser_model4)
my_model5 <- keras::unserialize_model(ser_model5)
我可以开始处理了。但如果我在
foreach()
循环中运行它:
places <- list( of things to run )
r <- foreach(i=places, .export = c("ser_model1", "ser_model2", "ser_model3", "ser_model4", "ser_model5"),
.packages = c("dplyr","av","imager","jpeg","tensorflow","keras","stringr","reticulate","caTools","imagerExtra","raster","readr","gsignal","data.table")) %dopar% {
#unserialize models locally
my_model1 <- keras::unserialize_model(ser_model1)
my_model2 <- keras::unserialize_model(ser_model2)
my_model3 <- keras::unserialize_model(ser_model3)
my_model4 <- keras::unserialize_model(ser_model4)
my_model5 <- keras::unserialize_model(ser_model5)
# lots of processing here
# eventually some_results <- whatever_computation()
return(some_results)
}
然后代码因
keras::unserialize_model(ser_model1)
调用上的段错误而崩溃:
2024-04-06 21:32:07.768352: I external/local_tsl/tsl/cuda/cudart_stub.cc:32] Could not find cuda drivers on your machine, GPU will not be used.
2024-04-06 21:32:07.773084: I external/local_tsl/tsl/cuda/cudart_stub.cc:32] Could not find cuda drivers on your machine, GPU will not be used.
2024-04-06 21:32:07.834125: I tensorflow/core/platform/cpu_feature_guard.cc:210] This TensorFlow binary is optimized to use available CPU instructions in performance-critical operations.
To enable the following instructions: AVX2 AVX512F FMA, in other operations, rebuild TensorFlow with the appropriate compiler flags.
2024-04-06 21:32:09.108273: W tensorflow/compiler/tf2tensorrt/utils/py_utils.cc:38] TF-TRT Warning: Could not find TensorRT
*** caught segfault ***
address (nil), cause 'memory not mapped'
Traceback:
1: conditionMessage_from_py_exception(c)
2: conditionMessage.python.builtin.BaseException(errorValue)
3: conditionMessage(errorValue)
4: sprintf("task %d failed - \"%s\"", errorIndex, conditionMessage(errorValue))
5: e$fun(obj, substitute(ex), parent.frame(), e$data)
6: Redacted foreach statement
7: calling_my_function_above()
8: perform_model(inputs)
An irrecoverable exception occurred. R is aborting now ...
Segmentation fault (core dumped)
这是我的会话信息:
R version 4.3.3 (2024-02-29)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 22.04.1 LTS
Matrix products: default
BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.10.0
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.10.0
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=en_US.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
time zone: UTC
tzcode source: system (glibc)
attached base packages:
[1] stats graphics grDevices datasets utils methods base
other attached packages:
[1] dplyr_1.1.4 rjson_0.2.21 hash_2.2.6.3 DBI_1.2.2 odbc_1.4.2
loaded via a namespace (and not attached):
[1] utf8_1.2.4 R6_2.5.1 tidyselect_1.2.1 bit_4.0.5
[5] magrittr_2.0.3 glue_1.7.0 bspm_0.5.5.1 blob_1.2.4
[9] tibble_3.2.1 pkgconfig_2.0.3 generics_0.1.3 bit64_4.0.5
[13] lifecycle_1.0.4 cli_3.6.2 fansi_1.0.6 vctrs_0.6.5
hms_1.1.3 pillar_1.9.0 Rcpp_1.0.12
[21] rlang_1.1.3
如上所述,删除
foreach()
似乎可以让代码继续前进。我已将线程数从 8 个更改为 2 个。并且我尝试尽可能地减少代码。问题似乎出在对 my_model1
的呼吁上。如果我注释掉它(并保留其他 unserialize_model()
调用),代码将继续执行而不会导致段错误。
也许“找不到 TensorRT”警告是一个问题,但由于其他调用工作没有问题,所以我必须相信这不是问题。 (是吗?)
如何了解导致崩溃的
ser_model1
的有趣之处?为什么调用堆栈中显示的“任务失败”消息从未被打印?似乎它会提供一些见解。当 R 导致段错误并且涉及许多其他库和依赖项时,我该如何调试 R?
使用 TensorFlow 分叉进程并不安全。 TensorFlow 维护自己的线程池,尝试分叉主进程将导致段错误。无论您使用的是 Python 还是 R 接口,都是如此。
因此,在 R 中使用任何分叉当前 R 进程的并行化方法都行不通。这包括
foreach
、mclapply
等。