Re: [2/3] ntdll: Implement NtQuerySystemInformation/SystemLogicalProcessorInformation (try 5)
Rudolf Mayerhofer <rm(a)eightyfive.net> writes:
+/*********************************************************************** + * Several methods to retrieve data from SysFS (/sys) + * used to retrieve cached_lpi in fill_cpu_info() + */ +static int sysfs_cpu_exists(int cpu) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/cpu/cpu%d", cpu); + return access(buf, F_OK) == 0; +} + +static int sysfs_cpucache_exists(int cpu, int cache) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/cpu/cpu%d/cache/index%d", cpu, cache); + return access(buf, F_OK) == 0; +} + +static int sysfs_numanode_exists(int node) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/node/node%d", node); + return access(buf, F_OK) == 0; +}
Don't do that sort of thing. You should handle failures to open the files at the point where you need them instead of doing redundant checks. -- Alexandre Julliard julliard(a)winehq.org
On Friday 08 October 2010 14:26:28 Alexandre Julliard wrote:
Rudolf Mayerhofer <rm(a)eightyfive.net> writes:
+/*********************************************************************** + * Several methods to retrieve data from SysFS (/sys) + * used to retrieve cached_lpi in fill_cpu_info() + */ +static int sysfs_cpu_exists(int cpu) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/cpu/cpu%d", cpu); + return access(buf, F_OK) == 0; +} + +static int sysfs_cpucache_exists(int cpu, int cache) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/cpu/cpu%d/cache/index%d", cpu, cache); + return access(buf, F_OK) == 0; +} + +static int sysfs_numanode_exists(int node) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/node/node%d", node); + return access(buf, F_OK) == 0; +}
Don't do that sort of thing. You should handle failures to open the files at the point where you need them instead of doing redundant checks.
That's not the case here, these checks are simply to find out if a cpu,cpu cache or numa node index exists in SysFS. It just makes no sense to try to parse all of the stuff for a specific cpu index if it does not exist in the first place and this is the check for that (it's done the same way as lscpu from util-linux-ng does it). All the parsing functions have their own error handling as well.
On Friday 08 October 2010 14:26:28 Alexandre Julliard wrote:
Rudolf Mayerhofer <rm(a)eightyfive.net> writes:
+/*********************************************************************** + * Several methods to retrieve data from SysFS (/sys) + * used to retrieve cached_lpi in fill_cpu_info() + */ +static int sysfs_cpu_exists(int cpu) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/cpu/cpu%d", cpu); + return access(buf, F_OK) == 0; +} + +static int sysfs_cpucache_exists(int cpu, int cache) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/cpu/cpu%d/cache/index%d", cpu, cache); + return access(buf, F_OK) == 0; +} + +static int sysfs_numanode_exists(int node) +{ + char buf[256]; + + sprintf(buf, "/sys/devices/system/node/node%d", node); + return access(buf, F_OK) == 0; +}
Don't do that sort of thing. You should handle failures to open the files at the point where you need them instead of doing redundant checks.
That's not the case here, these checks are simply to find out if a cpu,cpu cache or numa node index exists in SysFS. It just makes no sense to try to parse all of the stuff for a specific cpu index if it does not exist in the first place and this is the check for that (it's done the same way as lscpu from util-linux-ng does it).
All the parsing functions have their own error handling as well.
To clarify things a bit more, those checks are always on directories. For CPU/Cache/Numa Node there is on directory containing files and subdirectories with all the data belonging to that CPU/Cache/Numa Node. The indicies are always from 0 up to n (n=Max Number of Elements for each type). An error at the point where the data is parsed is not enough to determine if the CPU/Cache/Numa Node itself missing (which means we have already parsed all known elements) or the datafile is inaccessible/missing. Thus the additional check if the basedirectory for the CPU/Cache/Numa Node exists.
participants (2)
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Alexandre Julliard -
Rudolf Mayerhofer