Added by 培旭 6 months ago. Updated 6 months ago.
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Description
烧录固件，第一次读写速度写速度（小于50M/s）过低，再次开机，读写速度正常
使用conv=fdatasync参数，写入emmc分为两部分，1.内存缓存写入时间 2. 内存缓存最终同步到磁盘的时间，根据下面测试结果来看，主要问题出现在1.内存缓存写入时间 ，具体原因待排查
测试命令：
time sudo strace -e trace=fdatasync -ttt -o time.txt dd if=/dev/zero of=./jie.txt bs=16k count=64 conv=fdatasync
正常情况的测试结果：
neardi@LPA3588:~/jie$ time sudo strace -e trace=fdatasync -ttt -o time.txt dd if=/dev/zero of=./jie.txt
bs=16k count=64 conv=fdatasync
64+0 records in
64+0 records out
1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.0396813 s, 26.4 MB/s
real 0m0.153s
user 0m0.020s
sys 0m0.064s
neardi@LPA3588:~/jie$ cat time.txt
1722422078.502206 fdatasync(1) = 0
1722422078.526214 ++ exited with 0 ++
异常情况的测试结果：
neardi@LPA3588:~/jie$ time strace -e trace=fdatasync -ttt -o timeout.txt dd if=/dev/zero of=./jie.txt bs=16k count=64 conv=fdatasync
64+0 records in
64+0 records out
1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.317076 s, 3.3 MB/s
real 0m0.365s
user 0m0.013s
sys 0m0.108s
neardi@LPA3588:~/jie$ cat timeout.txt
1722423400.896093 fdatasync(1) = 0
1722423400.908384 ++ exited with 0 ++
neardi@LPA3588:~/jie$