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by microtherion 3297 days ago
This works easily for the default case, which prints "y\n" (two bytes), which is likely to divide BUFSIZ. To handle the general case with the same efficiency, you have to have a buffer size that is a multiple of both BUFSIZ and the length of the string to be printed. It appears that GNU yes will not do that and simply does unaligned writes in this case, which is likely to be considerably slower (possibly slower than write would have been).
1 comments
masklinn 3297 days ago
> It appears that GNU yes will not do that and simply does unaligned writes in this case, which is likely to be considerably slower (possibly slower than write would have been).

Why would it be slower to do a single, say, 8190 bytes write instead of 2730 3-byte writes?

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AstralStorm 3297 days ago
Generally writes not aligned to cache line are slightly slower on most common architectures, vastly slower on others. (Such as many MIPS)

Small write calls themselves incur a considerable syscall overhead.

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