mirror of
https://gitlab.freedesktop.org/pipewire/pipewire.git
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85d5c8cd6c
Add a method to enable/disable the denormals flush-to-zero and denormals-as-zero CPU options. Add a config option to make it possible to disable this again. Fixes high CPU usage when dealing with denormals, which can happen in many DSP functions. Fixes #1681
162 lines
3.7 KiB
C
162 lines
3.7 KiB
C
/* Spa
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*
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* Copyright © 2019 Wim Taymans
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <spa/utils/string.h>
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#define MAX_BUFFER 4096
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static char *get_cpuinfo_line(char *cpuinfo, const char *tag)
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{
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char *line, *end, *colon;
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if (!(line = strstr(cpuinfo, tag)))
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return NULL;
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if (!(end = strchr(line, '\n')))
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return NULL;
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if (!(colon = strchr(line, ':')))
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return NULL;
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if (++colon >= end)
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return NULL;
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return strndup(colon, end - colon);
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}
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static char *get_cpuinfo(void)
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{
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char *cpuinfo;
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int n, fd;
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cpuinfo = malloc(MAX_BUFFER);
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if ((fd = open("/proc/cpuinfo", O_RDONLY | O_CLOEXEC, 0)) < 0) {
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free(cpuinfo);
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return NULL;
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}
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if ((n = read(fd, cpuinfo, MAX_BUFFER-1)) < 0) {
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free(cpuinfo);
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close(fd);
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return NULL;
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}
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cpuinfo[n] = 0;
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close(fd);
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return cpuinfo;
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}
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static int
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arm_init(struct impl *impl)
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{
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uint32_t flags = 0;
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char *cpuinfo, *line;
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int arch;
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if (!(cpuinfo = get_cpuinfo())) {
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spa_log_warn(impl->log, "%p: Can't read cpuinfo", impl);
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return 1;
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}
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if ((line = get_cpuinfo_line(cpuinfo, "CPU architecture"))) {
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arch = strtoul(line, NULL, 0);
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if (arch >= 6)
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flags |= SPA_CPU_FLAG_ARMV6;
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if (arch >= 8)
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flags |= SPA_CPU_FLAG_ARMV8;
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free(line);
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}
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if ((line = get_cpuinfo_line(cpuinfo, "Features"))) {
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char *state = NULL;
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char *current = strtok_r(line, " ", &state);
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do {
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#if defined (__aarch64__)
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if (spa_streq(current, "asimd"))
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flags |= SPA_CPU_FLAG_NEON;
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else if (spa_streq(current, "fp"))
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flags |= SPA_CPU_FLAG_VFPV3 | SPA_CPU_FLAG_VFP;
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#else
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if (spa_streq(current, "vfp"))
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flags |= SPA_CPU_FLAG_VFP;
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else if (spa_streq(current, "neon"))
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flags |= SPA_CPU_FLAG_NEON;
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else if (spa_streq(current, "vfpv3"))
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flags |= SPA_CPU_FLAG_VFPV3;
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#endif
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} while ((current = strtok_r(NULL, " ", &state)));
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free(line);
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}
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free(cpuinfo);
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impl->flags = flags;
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return 0;
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}
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static int arm_zero_denormals(void *object, bool enable)
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{
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#if defined(__aarch64__)
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uint64_t cw;
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if (enable)
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__asm__ __volatile__(
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"mrs %0, fpcr \n"
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"orr %0, %0, #0x1000000 \n"
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"msr fpcr, %0 \n"
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"isb \n"
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: "=r"(cw)::"memory");
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else
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__asm__ __volatile__(
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"mrs %0, fpcr \n"
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"and %0, %0, #~0x1000000 \n"
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"msr fpcr, %0 \n"
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"isb \n"
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: "=r"(cw)::"memory");
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#else
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uint32_t cw;
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if (enable)
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__asm__ __volatile__(
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"vmrs %0, fpscr \n"
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"orr %0, %0, #0x1000000 \n"
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"vmsr fpscr, %0 \n"
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: "=r"(cw)::"memory");
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else
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__asm__ __volatile__(
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"vmrs %0, fpscr \n"
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"and %0, %0, #~0x1000000 \n"
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"vmsr fpscr, %0 \n"
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: "=r"(cw)::"memory");
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#endif
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return 0;
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}
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