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Remove IOSTATS_ADD_IF_POSITIVE() (#8984)

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Summary:
IOSTATS_ADD_IF_POSITIVE() doesn't seem to a macro that aims to improve performance but does the opposite. The counter to add is almost always positive so the if is just a waste. Furthermore, adding to a thread local variable seemse to be much cheaper than an if condition if branch prediction has a possibility to be wrong. Remove the macro.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8984

Test Plan: See CI completes.

Reviewed By: anand1976

Differential Revision: D31348163

fbshipit-source-id: 30af6d45e1aa8bbc09b2c046206cce6f67f4777a
This commit is contained in:
sdong 2021-10-01 14:41:58 -07:00 committed by Facebook GitHub Bot
parent e5bfb91d09
commit 7f08a8503f
2 changed files with 2 additions and 6 deletions
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4
file/random_access_file_reader.cc
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@ -181,7 +181,7 @@ IOStatus RandomAccessFileReader::Read(const IOOptions& opts, uint64_t offset,
} }
*result = Slice(res_scratch, io_s.ok() ? pos : 0); *result = Slice(res_scratch, io_s.ok() ? pos : 0);
} }
IOSTATS_ADD_IF_POSITIVE(bytes_read, result->size()); IOSTATS_ADD(bytes_read, result->size());
SetPerfLevel(prev_perf_level); SetPerfLevel(prev_perf_level);
} }
if (stats_ != nullptr && file_read_hist_ != nullptr) { if (stats_ != nullptr && file_read_hist_ != nullptr) {
@ -346,7 +346,7 @@ IOStatus RandomAccessFileReader::MultiRead(const IOOptions& opts,
start_ts, finish_ts, read_reqs[i].status); start_ts, finish_ts, read_reqs[i].status);
} }
#endif // ROCKSDB_LITE #endif // ROCKSDB_LITE
IOSTATS_ADD_IF_POSITIVE(bytes_read, read_reqs[i].result.size()); IOSTATS_ADD(bytes_read, read_reqs[i].result.size());
} }
SetPerfLevel(prev_perf_level); SetPerfLevel(prev_perf_level);
} }

4
monitoring/iostats_context_imp.h
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@ -15,10 +15,6 @@ extern __thread IOStatsContext iostats_context;
// increment a specific counter by the specified value // increment a specific counter by the specified value
#define IOSTATS_ADD(metric, value) (iostats_context.metric += value) #define IOSTATS_ADD(metric, value) (iostats_context.metric += value)
// Increase metric value only when it is positive
#define IOSTATS_ADD_IF_POSITIVE(metric, value) \
if (value > 0) { IOSTATS_ADD(metric, value); }
// reset a specific counter to zero // reset a specific counter to zero
#define IOSTATS_RESET(metric) (iostats_context.metric = 0) #define IOSTATS_RESET(metric) (iostats_context.metric = 0)