[THRIFT-1642] Miscalculation lead to throw unexpected "TTransportException::TIMED_OUT"(or called "EAGAIN (timed out)") exception

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.8
• Fix Version/s: 0.9.3
• Component/s: C++ - Library

Environment

GNU/Linux x86_64

• Assignee: James E. King III
• Reporter: catxl
• Created: 04/Jul/12 02:29
• Updated: 21/Jul/15 02:21
• Resolved: 10/May/15 12:44

Description

In function 'uint32_t TSocket::read(uint8_t* buf, uint32_t len)', there's an miscalculation which can lead to wrong judgment:

struct timeval begin;
gettimeofday(&begin, NULL);
//
// do some thing
//
struct timeval end;
gettimeofday(&end, NULL);
uint32_t readElapsedMicros = (((end.tv_sec - begin.tv_sec) * 1000 * 1000)
+ (((uint64_t)(end.tv_usec - begin.tv_usec))));

'readElapsedMicros' will be very large when 'end.tv_usec < begin.tv_usec'.
This will lead to throw unexpected "TTransportException::TIMED_OUT"(or called "EAGAIN (timed out)") exception sometimes.

Besides,
(1)I don't think the "usleep(50);" call in the same function above is necessary, I think delete this call could improve performance.
(2)I don't know why 'readElapsedMicros' compare with 'eagainThresholdMicros', which is not the value (recvTimeout_*1000), but:
eagainThresholdMicros = (recvTimeout_*1000)/ ((maxRecvRetries_>0) ? maxRecvRetries_ : 2);
can anyone tell me someting about this? Thank you!