random: remove ifdef'd out interrupt bench

commit 95e6060c20a7f5db60163274c5222a725ac118f9 upstream.

With tools like kbench9000 giving more finegrained responses, and this
basically never having been used ever since it was initially added,
let's just get rid of this. There *is* still work to be done on the
interrupt handler, but this really isn't the way it's being developed.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 950b0d6a630771a3bea8cfe49c0af401fb9ed8c9..5cbdff822e41429a83fcf6cb2bcb1c7806f5dd10 100644 (file)
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -852,15 +852,6 @@ This is a directory, with the following entries:
   are woken up. This file is writable for compatibility purposes, but
   writing to it has no effect on any RNG behavior.
 
-If ``drivers/char/random.c`` is built with ``ADD_INTERRUPT_BENCH``
-defined, these additional entries are present:
-
-* ``add_interrupt_avg_cycles``: the average number of cycles between
-  interrupts used to feed the pool;
-
-* ``add_interrupt_avg_deviation``: the standard deviation seen on the
-  number of cycles between interrupts used to feed the pool.
-
 
 randomize_va_space
 ==================

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 9b7367d00560c2fe00381b5d904f46da2353374b..511db57948c4f2e5da5303a42a0e4de17272195b 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -240,8 +240,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/random.h>
 
-/* #define ADD_INTERRUPT_BENCH */
-
 enum {
        POOL_BITS = BLAKE2S_HASH_SIZE * 8,
        POOL_MIN_BITS = POOL_BITS /* No point in settling for less. */
@@ -806,27 +804,6 @@ EXPORT_SYMBOL_GPL(add_input_randomness);
 
 static DEFINE_PER_CPU(struct fast_pool, irq_randomness);
 
-#ifdef ADD_INTERRUPT_BENCH
-static unsigned long avg_cycles, avg_deviation;
-
-#define AVG_SHIFT 8 /* Exponential average factor k=1/256 */
-#define FIXED_1_2 (1 << (AVG_SHIFT - 1))
-
-static void add_interrupt_bench(cycles_t start)
-{
-       long delta = random_get_entropy() - start;
-
-       /* Use a weighted moving average */
-       delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT);
-       avg_cycles += delta;
-       /* And average deviation */
-       delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT);
-       avg_deviation += delta;
-}
-#else
-#define add_interrupt_bench(x)
-#endif
-
 static u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
 {
        u32 *ptr = (u32 *)regs;
@@ -863,7 +840,6 @@ void add_interrupt_randomness(int irq)
                (sizeof(ip) > 4) ? ip >> 32 : get_reg(fast_pool, regs);
 
        fast_mix(fast_pool);
-       add_interrupt_bench(cycles);
 
        if (unlikely(crng_init == 0)) {
                if (fast_pool->count >= 64 &&
@@ -1571,22 +1547,6 @@ struct ctl_table random_table[] = {
                .mode           = 0444,
                .proc_handler   = proc_do_uuid,
        },
-#ifdef ADD_INTERRUPT_BENCH
-       {
-               .procname       = "add_interrupt_avg_cycles",
-               .data           = &avg_cycles,
-               .maxlen         = sizeof(avg_cycles),
-               .mode           = 0444,
-               .proc_handler   = proc_doulongvec_minmax,
-       },
-       {
-               .procname       = "add_interrupt_avg_deviation",
-               .data           = &avg_deviation,
-               .maxlen         = sizeof(avg_deviation),
-               .mode           = 0444,
-               .proc_handler   = proc_doulongvec_minmax,
-       },
-#endif
        { }
 };
 #endif /* CONFIG_SYSCTL */