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Support for large PT buffers (>=2G) #36

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21 changes: 13 additions & 8 deletions simple-pt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -270,6 +270,12 @@ static struct kernel_param_ops trace_stop_ops = {
/* Support for Linux panic dumps (optional) */

static int pt_num_buffers = 1;

static int get_topa_order(void)
{
return get_order((pt_num_buffers + 1) * 8);
}

static int log_dump = 0;
static void print_last_branches(int num_psbs);

Expand Down Expand Up @@ -674,7 +680,7 @@ static int simple_pt_buffer_init(int cpu)
if (!topa) {
int n;

topa = (u64 *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
topa = (u64 *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, get_topa_order());
if (!topa) {
pr_err("cpu %d, Cannot allocate topa page\n", cpu);
goto out_pt_buffer;
Expand Down Expand Up @@ -801,12 +807,12 @@ static long simple_pt_ioctl(struct file *file, unsigned int cmd,
return 0;
}
case SIMPLE_PT_GET_SIZE: {
int num = topa_entries(file_get_cpu(file));
u64 num = topa_entries(file_get_cpu(file));
return put_user(num * (PAGE_SIZE << pt_buffer_order),
(int *)arg);
(u64 *)arg);
}
case SIMPLE_PT_GET_OFFSET: {
unsigned offset;
u64 offset;
int ret = 0;
mutex_lock(&restart_mutex);
if (per_cpu(pt_running, file_get_cpu(file)))
Expand All @@ -815,7 +821,7 @@ static long simple_pt_ioctl(struct file *file, unsigned int cmd,
offset = per_cpu(pt_offset, file_get_cpu(file));
mutex_unlock(&restart_mutex);
if (!ret)
ret = put_user(offset, (int *)arg);
ret = put_user(offset, (u64 *)arg);
return ret;
}
default:
Expand Down Expand Up @@ -1094,8 +1100,7 @@ static int simple_pt_cpuid(void)
addr_cfg_max = 2;
if (!(c & BIT(1)))
pt_num_buffers = 1;
pt_num_buffers = min_t(unsigned, pt_num_buffers,
(PAGE_SIZE / 8) - 1);

a1 = b1 = c1 = d1 = 0;
if (a >= 1)
cpuid_count(0x14, 1, &a1, &b1, &c1, &d1);
Expand Down Expand Up @@ -1137,7 +1142,7 @@ static int spt_cpu_teardown(unsigned int cpu)
if (per_cpu(topa_cpu, cpu)) {
u64 *topa = per_cpu(topa_cpu, cpu);
free_topa(topa);
free_page((unsigned long)topa);
free_pages((unsigned long)topa, get_topa_order());
per_cpu(topa_cpu, cpu) = NULL;
}
if (per_cpu(pt_buffer_cpu, cpu)) {
Expand Down
29 changes: 23 additions & 6 deletions sptdump.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <inttypes.h>
#include <sys/mman.h>
#include <signal.h>
#include <sys/ioctl.h>
Expand All @@ -45,11 +46,26 @@

#define err(x) perror(x), exit(1)

size_t write_all(int fd, char *buf, size_t sz)
{
size_t left = sz;
while(left) {
size_t once = 1UL * 1024 * 1024 * 1024;
once = once > left ? left : once;
ssize_t ret = write(fd, buf, once);
if (ret <= 0)
err("write to file");
left -= ret;
buf += ret;
}
return sz;
}

int main(int ac, char **av)
{
int ncpus = sysconf(_SC_NPROCESSORS_CONF);
int pfds[ncpus];
int bufsize;
uint64_t bufsize;
char *pbuf[ncpus];

int i;
Expand Down Expand Up @@ -79,17 +95,18 @@ int main(int ac, char **av)
if (fd < 0)
err("Opening output file");

unsigned offset;
uint64_t offset;
if (ioctl(pfds[i], SIMPLE_PT_GET_OFFSET, &offset) < 0) {
perror("SIMPLE_PT_GET_OFFSET");
continue;
}

unsigned len = 0;
size_t len = 0;
if (*(uint64_t *)(pbuf[i] + offset))
len += write(fd, pbuf[i] + offset, bufsize - offset);
len += write(fd, pbuf[i], offset);
printf("cpu %3d offset %6u, %5u KB, writing to %s\n", i, offset, len >> 10, fn);
len += write_all(fd, pbuf[i] + offset, bufsize - offset);
len += write_all(fd, pbuf[i], offset);
printf("cpu %3d offset %6" PRIu64 ", %5zu KB, writing to %s\n", i, offset, len >> 10, fn);

close(fd);
if (len == 0)
unlink(fn);
Expand Down