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Merged
behlendorf merged 1 commit into from
Jul 30, 2025
Merged

Faster checksum benchmark on system boot #17563

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69 changes: 40 additions & 29 deletions module/zfs/zfs_chksum.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,9 +32,6 @@
#include <sys/blake3.h>
#include <sys/sha2.h>

/* limit benchmarking to max 256KiB, when EdonR is slower then this: */
#define LIMIT_PERF_MBS 300

typedef struct {
const char *name;
const char *impl;
Expand All @@ -52,9 +49,15 @@ typedef struct {
zio_checksum_tmpl_free_t *(free);
} chksum_stat_t;

#define AT_STARTUP 0
#define AT_BENCHMARK 1
#define AT_DONE 2

static chksum_stat_t *chksum_stat_data = 0;
static int chksum_stat_cnt = 0;
static kstat_t *chksum_kstat = NULL;
static int chksum_stat_limit = AT_STARTUP;
static int chksum_stat_cnt = 0;
static void chksum_benchmark(void);

/*
* Sample output on i3-1005G1 System:
Expand Down Expand Up @@ -129,6 +132,9 @@ chksum_kstat_data(char *buf, size_t size, void *data)
static void *
chksum_kstat_addr(kstat_t *ksp, loff_t n)
{
/* full benchmark */
chksum_benchmark();

if (n < chksum_stat_cnt)
ksp->ks_private = (void *)(chksum_stat_data + n);
else
Expand Down Expand Up @@ -176,47 +182,36 @@ chksum_run(chksum_stat_t *cs, abd_t *abd, void *ctx, int round,
kpreempt_enable();

run_bw = size * run_count * NANOSEC;
run_bw /= run_time_ns; /* B/s */
run_bw /= run_time_ns; /* B/s */
*result = run_bw/1024/1024; /* MiB/s */
}

#define LIMIT_INIT 0
#define LIMIT_NEEDED 1
#define LIMIT_NOLIMIT 2

static void
chksum_benchit(chksum_stat_t *cs)
{
abd_t *abd;
void *ctx = 0;
void *salt = &cs->salt.zcs_bytes;
static int chksum_stat_limit = LIMIT_INIT;

memset(salt, 0, sizeof (cs->salt.zcs_bytes));
if (cs->init)
ctx = cs->init(&cs->salt);

/* benchmarks in startup mode */
if (chksum_stat_limit == AT_STARTUP) {
abd = abd_alloc_linear(1<<18, B_FALSE);
chksum_run(cs, abd, ctx, 5, &cs->bs256k);
goto done;
}

/* allocate test memory via abd linear interface */
abd = abd_alloc_linear(1<<20, B_FALSE);

/* benchmarks when requested */
chksum_run(cs, abd, ctx, 1, &cs->bs1k);
chksum_run(cs, abd, ctx, 2, &cs->bs4k);
chksum_run(cs, abd, ctx, 3, &cs->bs16k);
chksum_run(cs, abd, ctx, 4, &cs->bs64k);
chksum_run(cs, abd, ctx, 5, &cs->bs256k);

/* check if we ran on a slow cpu */
if (chksum_stat_limit == LIMIT_INIT) {
if (cs->bs1k < LIMIT_PERF_MBS) {
chksum_stat_limit = LIMIT_NEEDED;
} else {
chksum_stat_limit = LIMIT_NOLIMIT;
}
}

/* skip benchmarks >= 1MiB when the CPU is to slow */
if (chksum_stat_limit == LIMIT_NEEDED)
goto abort;

chksum_run(cs, abd, ctx, 6, &cs->bs1m);
abd_free(abd);

Expand All @@ -225,7 +220,7 @@ chksum_benchit(chksum_stat_t *cs)
chksum_run(cs, abd, ctx, 7, &cs->bs4m);
chksum_run(cs, abd, ctx, 8, &cs->bs16m);

abort:
done:
abd_free(abd);

/* free up temp memory */
Expand All @@ -243,16 +238,21 @@ chksum_benchmark(void)
/* we need the benchmark only for the kernel module */
return;
#endif

chksum_stat_t *cs;
uint64_t max;
uint32_t id, cbid = 0, id_save;
const zfs_impl_t *blake3 = zfs_impl_get_ops("blake3");
const zfs_impl_t *sha256 = zfs_impl_get_ops("sha256");
const zfs_impl_t *sha512 = zfs_impl_get_ops("sha512");

/* benchmarks are done */
if (chksum_stat_limit == AT_DONE)
return;


/* count implementations */
chksum_stat_cnt = 2;
chksum_stat_cnt = 1; /* edonr */
chksum_stat_cnt += 1; /* skein */
chksum_stat_cnt += sha256->getcnt();
chksum_stat_cnt += sha512->getcnt();
chksum_stat_cnt += blake3->getcnt();
Expand Down Expand Up @@ -332,6 +332,17 @@ chksum_benchmark(void)
}
}
blake3->setid(id_save);

switch (chksum_stat_limit) {
case AT_STARTUP:
/* next time we want a full benchmark */
chksum_stat_limit = AT_BENCHMARK;
break;
case AT_BENCHMARK:
/* no further benchmarks */
chksum_stat_limit = AT_DONE;
break;
}
}

void
Expand All @@ -341,7 +352,7 @@ chksum_init(void)
blake3_per_cpu_ctx_init();
#endif

/* Benchmark supported implementations */
/* 256KiB benchmark */
chksum_benchmark();

/* Install kstats for all implementations */
Expand Down
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