don't hint POSIX_FADV_RANDOM
#7758
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Just for the context, from
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src/mmap_disk_io.cpp
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| @@ -142,7 +142,7 @@ namespace { | |||
| aux::open_mode_t file_mode_for_job(aux::mmap_disk_job* j) | |||
| { | |||
| aux::open_mode_t ret = aux::open_mode::read_only; | |||
| if (!(j->flags & disk_interface::sequential_access)) ret |= aux::open_mode::random_access; | |||
| if (!(j->flags & disk_interface::sequential_access)) ret |= aux::open_mode::sequential_access; | |||
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You forgot to remove the ! here. It makes logic to be reversed.
And confirmed by testing, I see regular reads using 2x readahead size, but torrent re-checking use 1x instead.
Suggested change
| if (!(j->flags & disk_interface::sequential_access)) ret |= aux::open_mode::sequential_access; | |
| if (j->flags & disk_interface::sequential_access) ret |= aux::open_mode::sequential_access; |
arvidn
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…ably warrants read-ahead. Some antecdotes suggests this improve read speed in some circumstances
arvidn
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@HanabishiRecca thanks for your testing and review! |
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Normal piece sizes, of 2 or 4 MiB, probably warrants read-ahead. Some antecdotes suggests this improve read speed in some circumstances.
The use of the internal open mode flag
random_accessis really used to hint sequential access, for when checking files. This patch, therefore, renames the flag tosequential_accessand makes it mean that instead.This is an internal flag so doesn't affect the user facing API.