Messages in this thread | | | Date | Thu, 7 Jan 2021 19:04:45 +0000 | From | Al Viro <> | Subject | Re: [x86] d55564cfc2: will-it-scale.per_thread_ops -5.8% regression |
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On Thu, Jan 07, 2021 at 10:47:07AM -0800, Linus Torvalds wrote:
> Now, the "whole entry" is just 8 bytes, so it's possible that it would > actually be faster to do a copy of the whole thing rather than write > just the 16 bits. But I got very nervous about it, because I could > easily see some threaded app actually changing the 'fd' (or the > 'event' field) in place (ie writing -1 to it as they close and re-use > it)
BTW, changing 'event' field in place from another thread is going to be interesting - you have two 16bit values next to each other and two CPUs modifying those with no exclusion. Sounds like a recipe for massive trouble...
Or am I missing something here?
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