Feature #3962
openosmo-trx: Use gcc attribute no_sanitize to run fine with ASan enabled
Added by pespin almost 5 years ago. Updated over 4 years ago.
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Description
So far we don't enable ASan during osmo-trx build because it adds too much overhead and makes it wrong incorrectly (too slow).
zecke informed that there's a gcc compile-time attribute to flag specific functions to be not covered by ASan. So we can run perf on osmo-trx, see the most CPU intensive functions and disable ASan on those.
https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes
Updated by pespin almost 5 years ago
Since we usually compile with "-fsanitize=address -fsanitize=undefined" in osmocom projects, we should probably use flags:
"no_sanitize_address no_sanitize_undefined"
I need to check what happens if compiled with a compiler which doesn't support those flags. Do we need to put it into some OSMO_SANITIZE_AVOID define which is set to empty based on compiler support?
Updated by pespin over 4 years ago
On my current laptop (i7) I can run osmo-trx with asan enabled without any issue. Using linux perf on a running osmo-trx, it can be seen ASan doesn't take a big amount of CPU:
0.66% 0.66% TxUpper0 libasan.so.5.0.0 [.] __asan::Allocator::Allocate 0.39% 0.39% RxUpper0 libasan.so.5.0.0 [.] __asan::Allocator::Allocate 0.32% 0.32% RxLower libasan.so.5.0.0 [.] __asan::Allocator::Allocate 0.31% 0.31% RxUpper0 libasan.so.5.0.0 [.] __interceptor_memset.part.0 0.26% 0.26% TxLower libasan.so.5.0.0 [.] __asan::Allocator::Allocate 0.21% 0.21% RxUpper0 libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::Put 0.16% 0.16% TxUpper0 libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::Put 0.16% 0.16% TxLower libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::Put 0.15% 0.15% RxUpper0 libasan.so.5.0.0 [.] __sanitizer::BufferedStackTrace::FastUnwindStack 0.11% 0.11% RxUpper0 libasan.so.5.0.0 [.] __asan::QuarantineCallback::Recycle 0.11% 0.11% TxUpper0 libasan.so.5.0.0 [.] __sanitizer::BufferedStackTrace::FastUnwindStack 0.10% 0.10% TxUpper0 libasan.so.5.0.0 [.] __sanitizer::CombinedAllocator<__sanitizer::SizeClassAllocator64<__asan::AP64> 0.09% 0.09% RxUpper0 libasan.so.5.0.0 [.] __interceptor_memset 0.09% 0.09% TxUpper0 libasan.so.5.0.0 [.] __sanitizer::Quarantine<__asan::QuarantineCallback, __asan::AsanChunk>::DoRecycle 0.09% 0.09% TxUpper0 libasan.so.5.0.0 [.] __asan::QuarantineCallback::Recycle 0.08% 0.08% TxLower libasan.so.5.0.0 [.] __sanitizer::BufferedStackTrace::FastUnwindStack 0.08% 0.08% RxUpper0 libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::find 0.08% 0.08% RxLower libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::Put 0.07% 0.07% RxUpper0 libasan.so.5.0.0 [.] __sanitizer::Quarantine<__asan::QuarantineCallback, __asan::AsanChunk>::DoRecycle 0.07% 0.07% TxLower libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::find 0.07% 0.07% RxLower libasan.so.5.0.0 [.] __sanitizer::mem_is_zero 0.06% 0.06% TxLower libasan.so.5.0.0 [.] __asan_region_is_poisoned 0.06% 0.06% TxLower libasan.so.5.0.0 [.] __interceptor_memcpy.part.0 0.06% 0.06% TxUpper0 libasan.so.5.0.0 [.] __interceptor_memcpy.part.0 0.06% 0.06% RxLower libasan.so.5.0.0 [.] __sanitizer::BufferedStackTrace::FastUnwindStack 0.06% 0.06% RxUpper0 libasan.so.5.0.0 [.] __sanitizer::CombinedAllocator<__sanitizer::SizeClassAllocator64<__asan::AP64>,__sanitizer::SizeClassAllocatorLocalCache<__sanitizer::SizeClassAllocato 0.06% 0.06% TxUpper0 libasan.so.5.0.0 [.] __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::find 0.06% 0.06% RxUpper0 libasan.so.5.0.0 [.] __asan::Allocator::QuarantineChunk 0.06% 0.06% TxLower libasan.so.5.0.0 [.] __asan::Allocator::QuarantineChunk 0.06% 0.06% TxLower libasan.so.5.0.0 [.] __sanitizer::CombinedAllocator<__sanitizer::SizeClassAllocator64<__asan::AP64>,sanitizer::SizeClassAllocatorLocalCache<__sanitizer::SizeClassAllocato 0.05% 0.05% RxLower libasan.so.5.0.0 [.] __asan_region_is_poisoned ...
So roughly around 5% of CPU time per thread.
Updated by pespin over 4 years ago
Most noticeable resource user in Asan (1.14% of CPU) is here:
- 1.14% 0.55% TxUpper0 libasan.so.5.0.0 [.] __asan::Allocator::Allocate
0.59% __asan::Allocator::Allocate
- 0.55% TxUpperLoopAdapter
Transceiver::driveTxPriorityQueue
- 1.14% 0.00% TxUpper0 libasan.so.5.0.0 [.] __asan::asan_memalign
__asan::asan_memalign
__asan::Allocator::Allocate
So some memory allocation under Transceiver::driveTxPriorityQueue, probably this part of the code:
BitVector newBurst(burstLen);
BitVector::iterator itr = newBurst.begin();
uint8_t *bufferItr = dl->soft_bits;
while (itr < newBurst.end())
*itr++ = *bufferItr++;
GSM::Time currTime = GSM::Time(fn, dl->common.tn);
addRadioVector(chan, newBurst, dl->tx_att, currTime);
That's probably some code we want to optimize and simply pass a pointer to dl->soft_bits (or using mempcy) to get rid of all that heap allocation + loop copying.
