Messages in this thread Patch in this message | | | Date | Mon, 31 Jan 2000 21:45:50 +0100 (CET) | From | Rik van Riel <> | Subject | [PATCH] cacheflushtime |
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Hi Linus,
taking the hint from someone who's name I'm too lazy to lookup in my mailfolder (sorry), I've decided to take it on me to create this small patch against 2.3.41 that fixes the cacheflushtime calculation.
Linus, could you please apply this patch for the next version?
regards,
Rik -- The Internet is not a network of computers. It is a network of people. That is its real strength.
--- linux-2.3.41/arch/i386/kernel/smpboot.c.orig Mon Jan 31 15:43:02 2000 +++ linux-2.3.41/arch/i386/kernel/smpboot.c Mon Jan 31 15:53:00 2000 @@ -710,7 +710,8 @@ static void smp_tune_scheduling (void) { - unsigned long cachesize; + unsigned long cachesize; /* kB */ + unsigned long bandwidth = 350; /* MB/s */ /* * Rough estimation for SMP scheduling, this is the number of * cycles it takes for a fully memory-limited process to flush @@ -731,10 +732,12 @@ return; } else { cachesize = boot_cpu_data.x86_cache_size; - if (cachesize == -1) - cachesize = 8; /* Pentiums */ + if (cachesize == -1) { + cachesize = 16; /* Pentiums, 2x8kB cache */ + bandwidth = 100; + } - cacheflush_time = cpu_hz/1024*cachesize/5000; + cacheflush_time = (cpu_hz>>20) * (cachesize<<10) / bandwidth; } printk("per-CPU timeslice cutoff: %ld.%02ld usecs.\n",
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