Avoid redfine of IO_SIZE if made configurable#265
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ericherman wants to merge 1 commit intomariadb-corporation:masterfrom
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Avoid redfine of IO_SIZE if made configurable#265ericherman wants to merge 1 commit intomariadb-corporation:masterfrom
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The default IO_SIZE of 4096 as defined in include/my_global.h and also in libmariadb's include/ma_global.h matches to the memory page size of most systems. Larger page sizes are widely supported, called "huge pages" in Linux, "superpages" in FreeBSD, and "large pages" in MS Windows. On POSIX systems, obtaining the page size can be done via: page_size= sysconf(_SC_PAGESIZE); On Windows: SYSTEM_INFO si; GetSystemInfo(&si); page_size= si.dwPageSize; Making mariadb's IO_SIZE configurable enables more straight-forward investigation of the performance implications of having an IO_SIZE which is different than the memory page size. Note that libmariadb's include/ma_global.h should also be adjusted to avoid a double #define of IO_SIZE and to ensure they are defined to be the same. See: mariadb-corporation/mariadb-connector-c#265 Signed-off-by: Eric Herman <[email protected]>
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include/ma_global.h
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| #endif | ||
| #if ((IO_SIZE <= 0) || ((IO_SIZE % 512) != 0) || ((IO_SIZE & (IO_SIZE-1)) != 0)) | ||
| #error "IO_SIZE must be a positive multiple of 512 and power of 2" | ||
| #endif |
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I don't like that, there's no reason — that I can see — why server's IO_SIZE should affect the client. I'd suggest to rename IO_SIZE in the libmariadb. See how it's used, perhaps a NET_BUFF_ALIGN could be a good name
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I would be perfectly happy to rename client constant instead as I also feel like these should be able to be distinct; @9E0R9 what do you think?
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I've updated and --force pushed
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Making mariadb's IO_SIZE compile-time configurable enables more straight-forward investigation of the performance implications of having an IO_SIZE which is different than the memory page size. The default IO_SIZE of 4096 as defined in include/my_global.h and also in libmariadb's include/ma_global.h matches to the memory page size of most systems. Larger page sizes are widely supported, called "huge pages" in Linux, "superpages" in FreeBSD, and "large pages" in MS Windows. On POSIX systems, obtaining the page size can be done via: page_size= sysconf(_SC_PAGESIZE); On Windows: SYSTEM_INFO si; GetSystemInfo(&si); page_size= si.dwPageSize; In https://jira.mariadb.org/browse/MDEV-35740 Marko highlights that there are vastly different uses of IO_SIZE. This "one size fits all" nature of IO_SIZE is not ideal, future work could split this into separate constants based upon usage. Note that libmariadb's include/ma_global.h should also be adjusted to avoid a double #define of IO_SIZE and to ensure they are defined to be the same. See: mariadb-corporation/mariadb-connector-c#265 Signed-off-by: Eric Herman <[email protected]>
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Making mariadb's IO_SIZE compile-time configurable enables more straight-forward investigation of the performance implications of having an IO_SIZE which is different than the memory page size. The default IO_SIZE of 4096 as defined in include/my_global.h and also in libmariadb's include/ma_global.h matches to the memory page size of most systems. Larger page sizes are widely supported, called "huge pages" in Linux, "superpages" in FreeBSD, and "large pages" in MS Windows. On POSIX systems, obtaining the page size can be done via: page_size= sysconf(_SC_PAGESIZE); On Windows: SYSTEM_INFO si; GetSystemInfo(&si); page_size= si.dwPageSize; In https://jira.mariadb.org/browse/MDEV-35740 Marko highlights that there are vastly different uses of IO_SIZE. This "one size fits all" nature of IO_SIZE is not ideal, future work could split this into separate constants based upon usage. Note that libmariadb's include/ma_global.h should also be adjusted to avoid a double #define of IO_SIZE and to ensure they are defined to be the same. See: mariadb-corporation/mariadb-connector-c#265 Signed-off-by: Eric Herman <[email protected]>
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Making mariadb's IO_SIZE compile-time configurable enables more straight-forward investigation of the performance implications of having an IO_SIZE which is different than the memory page size. The default IO_SIZE of 4096 as defined in include/my_global.h and also in libmariadb's include/ma_global.h matches to the memory page size of most systems. Larger page sizes are widely supported, called "huge pages" in Linux, "superpages" in FreeBSD, and "large pages" in MS Windows. On POSIX systems, obtaining the page size can be done via: page_size= sysconf(_SC_PAGESIZE); On Windows: SYSTEM_INFO si; GetSystemInfo(&si); page_size= si.dwPageSize; In https://jira.mariadb.org/browse/MDEV-35740 Marko highlights that there are vastly different uses of IO_SIZE. This "one size fits all" nature of IO_SIZE is not ideal, future work could split this into separate constants based upon usage. Note that libmariadb's include/ma_global.h should also be adjusted to avoid a double #define of IO_SIZE and to ensure they are defined to be the same. See: mariadb-corporation/mariadb-connector-c#265 Signed-off-by: Eric Herman <[email protected]>
The server's definition of IO_SIZE is re-used here in the client for network buffer alignment, however IO_SIZE is used in the server for many different things and the client's buffer alignment is not related to many of those uses. If the server is to make IO_SIZE configurable, we need to avoid either redefining it, or defining it to be different. By creating a specific define for this, we avoid redfine and clarify the code. See: MariaDB/server#3726 Signed-off-by: Eric Herman <[email protected]>
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Making mariadb's IO_SIZE compile-time configurable enables more straight-forward investigation of the performance implications of having an IO_SIZE which is different than the memory page size. The default IO_SIZE of 4096 as defined in include/my_global.h and also in libmariadb's include/ma_global.h matches to the memory page size of most systems. Larger page sizes are widely supported, called "huge pages" in Linux, "superpages" in FreeBSD, and "large pages" in MS Windows. On POSIX systems, obtaining the page size can be done via: page_size= sysconf(_SC_PAGESIZE); On Windows: SYSTEM_INFO si; GetSystemInfo(&si); page_size= si.dwPageSize; In https://jira.mariadb.org/browse/MDEV-35740 Marko highlights that there are vastly different uses of IO_SIZE. This "one size fits all" nature of IO_SIZE is not ideal, future work could split this into separate constants based upon usage. Note that libmariadb's include/ma_global.h should also be adjusted to avoid a double #define of IO_SIZE and to ensure they are defined to be the same. See: mariadb-corporation/mariadb-connector-c#265 Signed-off-by: Eric Herman <[email protected]>
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This PR Closed and replaced by: #267
If the server is to make IO_SIZE configurable, we need to avoid either redefining it, or defining it to be different.
See: MariaDB/server#3726 and https://jira.mariadb.org/browse/MDEV-35740