Messages in this thread | | | Date | Tue, 08 Apr 2008 13:44:05 -0700 | From | Mike Travis <> | Subject | Re: [PATCH 1/3] x86: modify show_shared_cpu_map in intel_cacheinfo v3 |
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Bert Wesarg wrote: > On Tue, Apr 8, 2008 at 8:43 PM, Mike Travis <travis@sgi.com> wrote: >> --- linux-2.6.x86.sched.orig/arch/x86/kernel/cpu/intel_cacheinfo.c >> +++ linux-2.6.x86.sched/arch/x86/kernel/cpu/intel_cacheinfo.c >> @@ -591,20 +591,34 @@ static ssize_t show_size(struct _cpuid4_ >> return sprintf (buf, "%luK\n", this_leaf->size / 1024); >> } >> >> -static ssize_t show_shared_cpu_map(struct _cpuid4_info *this_leaf, char *buf) >> +static ssize_t show_shared_cpu_map_func(struct _cpuid4_info *this_leaf, >> + int type, char *buf) > I don't know if this is more efficient or better or cleaner, but how > about to pass the function pointer (ie. cpulist_scnprintf or > cpumap_scnprintf)? You safe at least one condition. > >> + n = type? >> + cpulist_scnprintf(buf, len-2, *mask): >> + cpumask_scnprintf(buf, len-2, *mask); > > Thanks. > Bert
I have to subvert the cpumask interface a bit, but the resultant code size is about 7 instructions smaller.
static ssize_t show_shared_cpu_map_func(struct _cpuid4_info *this_leaf, int (*cpumap_func)(char *, int, const cpumask_t *, int), char *buf) { ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; int n = 0;
if (len > 1) { cpumask_t *mask = &this_leaf->shared_cpu_map; n = cpumap_func(buf, len-2, mask, NR_CPUS); buf[n++] = '\n'; buf[n] = '\0'; } return n; }
static inline ssize_t show_shared_cpu_map(struct _cpuid4_info *leaf, char *buf) { return show_shared_cpu_map_func(leaf, &__cpumask_scnprintf, buf); }
static inline ssize_t show_shared_cpu_list(struct _cpuid4_info *leaf, char *buf) { return show_shared_cpu_map_func(leaf, &__cpulist_scnprintf, buf); }
Btw, you were asking about how to determine NR_CPUS. Here's one way:
root@newton:~# cat /sys/devices/system/cpu/online 0-2,4-7 root@newton:~# cat /sys/devices/system/cpu/possible 0-511 root@newton:~# cat /sys/devices/system/cpu/present 0-7 root@newton:~# cat /sys/devices/system/cpu/system 0-4095
Thanks, Mike
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