From 34ff636f322c6d5e4f0a52338fa63a7dff09a495 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sat, 18 Jul 2026 13:15:36 -0400 Subject: scftorture: Count single_rpc offline failures in statistics output scf_torture_stats_print() aggregates each invoker thread's counters into a local scf_statistics structure before printing, but the n_single_rpc_ofl field is missing from the aggregation loop. As a result, the "single_rpc_ofl" value printed in the statistics line is always zero, even when smp_call_function_single() invocations for the RPC test have failed due to offline CPUs and been counted by the invoker threads. Add the missing accumulation so that the printed value reflects the actual counts. Signed-off-by: Joel Fernandes Signed-off-by: Paul E. McKenney --- lib/math/int_log.c | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 lib/math/int_log.c (limited to 'lib/math/int_log.c') diff --git a/lib/math/int_log.c b/lib/math/int_log.c new file mode 100644 index 000000000..8f9da3a2a --- /dev/null +++ b/lib/math/int_log.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: LGPL-2.1-or-later +/* + * Provides fixed-point logarithm operations. + * + * Copyright (C) 2006 Christoph Pfister (christophpfister@gmail.com) + */ + +#include +#include +#include +#include +#include + +#include + +static const unsigned short logtable[256] = { + 0x0000, 0x0171, 0x02e0, 0x044e, 0x05ba, 0x0725, 0x088e, 0x09f7, + 0x0b5d, 0x0cc3, 0x0e27, 0x0f8a, 0x10eb, 0x124b, 0x13aa, 0x1508, + 0x1664, 0x17bf, 0x1919, 0x1a71, 0x1bc8, 0x1d1e, 0x1e73, 0x1fc6, + 0x2119, 0x226a, 0x23ba, 0x2508, 0x2656, 0x27a2, 0x28ed, 0x2a37, + 0x2b80, 0x2cc8, 0x2e0f, 0x2f54, 0x3098, 0x31dc, 0x331e, 0x345f, + 0x359f, 0x36de, 0x381b, 0x3958, 0x3a94, 0x3bce, 0x3d08, 0x3e41, + 0x3f78, 0x40af, 0x41e4, 0x4319, 0x444c, 0x457f, 0x46b0, 0x47e1, + 0x4910, 0x4a3f, 0x4b6c, 0x4c99, 0x4dc5, 0x4eef, 0x5019, 0x5142, + 0x526a, 0x5391, 0x54b7, 0x55dc, 0x5700, 0x5824, 0x5946, 0x5a68, + 0x5b89, 0x5ca8, 0x5dc7, 0x5ee5, 0x6003, 0x611f, 0x623a, 0x6355, + 0x646f, 0x6588, 0x66a0, 0x67b7, 0x68ce, 0x69e4, 0x6af8, 0x6c0c, + 0x6d20, 0x6e32, 0x6f44, 0x7055, 0x7165, 0x7274, 0x7383, 0x7490, + 0x759d, 0x76aa, 0x77b5, 0x78c0, 0x79ca, 0x7ad3, 0x7bdb, 0x7ce3, + 0x7dea, 0x7ef0, 0x7ff6, 0x80fb, 0x81ff, 0x8302, 0x8405, 0x8507, + 0x8608, 0x8709, 0x8809, 0x8908, 0x8a06, 0x8b04, 0x8c01, 0x8cfe, + 0x8dfa, 0x8ef5, 0x8fef, 0x90e9, 0x91e2, 0x92db, 0x93d2, 0x94ca, + 0x95c0, 0x96b6, 0x97ab, 0x98a0, 0x9994, 0x9a87, 0x9b7a, 0x9c6c, + 0x9d5e, 0x9e4f, 0x9f3f, 0xa02e, 0xa11e, 0xa20c, 0xa2fa, 0xa3e7, + 0xa4d4, 0xa5c0, 0xa6ab, 0xa796, 0xa881, 0xa96a, 0xaa53, 0xab3c, + 0xac24, 0xad0c, 0xadf2, 0xaed9, 0xafbe, 0xb0a4, 0xb188, 0xb26c, + 0xb350, 0xb433, 0xb515, 0xb5f7, 0xb6d9, 0xb7ba, 0xb89a, 0xb97a, + 0xba59, 0xbb38, 0xbc16, 0xbcf4, 0xbdd1, 0xbead, 0xbf8a, 0xc065, + 0xc140, 0xc21b, 0xc2f5, 0xc3cf, 0xc4a8, 0xc580, 0xc658, 0xc730, + 0xc807, 0xc8de, 0xc9b4, 0xca8a, 0xcb5f, 0xcc34, 0xcd08, 0xcddc, + 0xceaf, 0xcf82, 0xd054, 0xd126, 0xd1f7, 0xd2c8, 0xd399, 0xd469, + 0xd538, 0xd607, 0xd6d6, 0xd7a4, 0xd872, 0xd93f, 0xda0c, 0xdad9, + 0xdba5, 0xdc70, 0xdd3b, 0xde06, 0xded0, 0xdf9a, 0xe063, 0xe12c, + 0xe1f5, 0xe2bd, 0xe385, 0xe44c, 0xe513, 0xe5d9, 0xe69f, 0xe765, + 0xe82a, 0xe8ef, 0xe9b3, 0xea77, 0xeb3b, 0xebfe, 0xecc1, 0xed83, + 0xee45, 0xef06, 0xefc8, 0xf088, 0xf149, 0xf209, 0xf2c8, 0xf387, + 0xf446, 0xf505, 0xf5c3, 0xf680, 0xf73e, 0xf7fb, 0xf8b7, 0xf973, + 0xfa2f, 0xfaea, 0xfba5, 0xfc60, 0xfd1a, 0xfdd4, 0xfe8e, 0xff47, +}; + +unsigned int intlog2(u32 value) +{ + /** + * returns: log2(value) * 2^24 + * wrong result if value = 0 (log2(0) is undefined) + */ + unsigned int msb; + unsigned int logentry; + unsigned int significand; + unsigned int interpolation; + + if (unlikely(value == 0)) { + WARN_ON(1); + return 0; + } + + /* first detect the msb (count begins at 0) */ + msb = fls(value) - 1; + + /** + * now we use a logtable after the following method: + * + * log2(2^x * y) * 2^24 = x * 2^24 + log2(y) * 2^24 + * where x = msb and therefore 1 <= y < 2 + * first y is determined by shifting the value left + * so that msb is bit 31 + * 0x00231f56 -> 0x8C7D5800 + * the result is y * 2^31 -> "significand" + * then the highest 9 bits are used for a table lookup + * the highest bit is discarded because it's always set + * the highest nine bits in our example are 100011000 + * so we would use the entry 0x18 + */ + significand = value << (31 - msb); + logentry = (significand >> 23) % ARRAY_SIZE(logtable); + + /** + * last step we do is interpolation because of the + * limitations of the log table the error is that part of + * the significand which isn't used for lookup then we + * compute the ratio between the error and the next table entry + * and interpolate it between the log table entry used and the + * next one the biggest error possible is 0x7fffff + * (in our example it's 0x7D5800) + * needed value for next table entry is 0x800000 + * so the interpolation is + * (error / 0x800000) * (logtable_next - logtable_current) + * in the implementation the division is moved to the end for + * better accuracy there is also an overflow correction if + * logtable_next is 256 + */ + interpolation = ((significand & 0x7fffff) * + ((logtable[(logentry + 1) % ARRAY_SIZE(logtable)] - + logtable[logentry]) & 0xffff)) >> 15; + + /* now we return the result */ + return ((msb << 24) + (logtable[logentry] << 8) + interpolation); +} +EXPORT_SYMBOL(intlog2); + +unsigned int intlog10(u32 value) +{ + /** + * returns: log10(value) * 2^24 + * wrong result if value = 0 (log10(0) is undefined) + */ + u64 log; + + if (unlikely(value == 0)) { + WARN_ON(1); + return 0; + } + + log = intlog2(value); + + /** + * we use the following method: + * log10(x) = log2(x) * log10(2) + */ + + return (log * 646456993) >> 31; +} +EXPORT_SYMBOL(intlog10); -- cgit v1.3.1